At Sacyr, protecting archaeological heritage is part of the way we deliver our projects. 

We work to safeguard historical finds and heritage assets wherever they appear. This commitment is also reflected in our training: in 2025, our professionals completed more than 3,700 hours of awareness programs on heritage preservation. 

These five recent projects show how we help protect the historical and cultural memory of the communities where we work. 

Almudévar Reservoir (Huesca, Spain) 

During construction of the Almudévar Reservoir, we recovered the remains of the south wall of the former Santo Domingo Hermitage, dating from the 12th and 13th centuries, and relocated it stone by stone. 

The wall is now part of the new hermitage, preserving the structure and keeping the site’s historical story alive. 

High-Speed Rail Line in Almería (Spain) 

Around Almería’s former railway station, we identified a concentration of finds suggesting the presence of an Islamic settlement, including abundant ceramics and hydraulic structures. The importance of these discoveries prompted a review of the heritage protection boundaries established in the urban planning framework. 

We also documented remains of Spanish Civil War air-raid shelters, including the so-called “workshops shelter” beneath the station’s former canopies. Although its condition made preservation impossible, it was recorded through 3D scanning and photography, and a commemorative marker was installed to preserve its memory. 

Loja Bypass, Antequera-Granada High-Speed Rail Line (Spain) 

In this project, we documented an extensive archaeological area around the site known as “Cerro de la Estación.” The preventive archaeological work allowed us to excavate more than 5,000 m² and identify dozens of structures, including pits, silos, and burial sites. The volume and spread of the remains meant the initially planned protection perimeter had to be expanded, contributing both to scientific knowledge and to the safeguarding of the site. 

Test excavations confirmed the presence of archaeological structures from periods spanning the Neolithic and the final stage of the Stone Age through to Late Antiquity, in the 5th century AD. 

The work documented Neolithic silos and burials, as well as rooms belonging to a Roman villa, together with a large quantity of archaeological material. 

Ibiza Wastewater Treatment Plant (Spain) 

The Ibiza Wastewater Treatment Plant project revealed a Roman road, a 16th-century irrigation channel, a Roman aqueduct and a Phoenician archaeological site of significant heritage value. Wall structures, a hydraulic structure, amphorae and a well were also found. 

“Taking part in this project was particularly interesting from both a technical and heritage perspective, as the works revealed a broad and diverse archaeological context,” explains Cristina Alonso Comba, site manager for the wastewater treatment plant. 

From a construction standpoint, this posed a major challenge. Construction solutions had to be continuously adapted so the project could move forward while preserving the most valuable elements. In some areas, the alignment and gradient were adjusted; in others, pipe jacking was used to protect significant structures and avoid direct impact. 

The archaeological remains and materials were handed over to the Museu Arqueològic d’Eivissa i Formentera for study and cataloging. 

Railway adaptation works in Mato Miranda (Portugal) 

In Mato de Miranda and Arneiro das Malhadas, we found a range of archaeological materials from the Late Neolithic or Chalcolithic period, including ceramic fragments, lithic artifacts, and remains of ancient domestic occupations. Found during archaeological monitoring of the work, these discoveries offer new insight into how this territory was inhabited over time. 

The ceramic fragments and lithic artifacts were handed over to Portugal’s Direção Geral do Património Cultural. 

Would you like to know more about how we protect the places where we operate? Read our Natural Capital Report 

MARÍA GÓMEZ BRAVO | Tungsteno

In the Nile Delta, many ancient Egyptian cities disappeared centuries ago beneath layers of sediment, farmland and modern development. From ground level, they are almost impossible to identify. Seen from space, however, some leave faint traces in the form of geometric lines, tonal variations or slight differences in soil moisture. Sarah Parcak, an Egyptologist and professor at the University of Alabama at Birmingham, has turned these subtle signals into a tool for locating potential archaeological sites without the need for prior excavation.

In the early 2010s, she participated in a number of projects focusing on ancient Egyptian settlements. In the Nile Delta, the contrast between cultivated land and desert areas makes it easier to detect small changes in the terrain that are invisible to the naked eye. Satellite imagery revealed geometric lines and subtle surface variations that corresponded to buried ancient structures. These were not visible ruins or cities emerging from the sand, but rather physical traces that the landscape had preserved for centuries.

Parcak began working with this type of imagery during her doctoral research at the University of Cambridge. Unlike conventional photographs, multispectral images capture information that the human eye cannot perceive. Her aim was to locate tells—mounds formed by successive layers of human occupation—and possible buried structures across the Middle East based on these minute alterations detected through infrared sensors. “To try to map the past, I have to look at it in a different way,” Parcak has said, summarising a central idea that runs through her research: landscapes preserve physical evidence of the people who inhabited them centuries ago.

Sarah Parcak explains how space archaeology uses satellite imagery to locate traces of ancient civilisations hidden beneath the ground. Credit: TED.

A new way of interpreting the landscape

The use of aerial imagery to study the terrain was not entirely new. After the First World War, photographs taken from military aircraft began to reveal ancient shapes and structures that were difficult to identify from the ground. Decades later, satellites from NASA’s Landsat programme made it possible to extend this observation to vast swathes of the planet and analyse how landscapes changed over time. But the real breakthrough lies not in conventional photography, but in understanding how buried structures affect soil, vegetation and temperature.

For example, a buried wall can alter the moisture content of the soil above it. Similarly, an adobe structure can change soil compaction and affect vegetation growth. Some constructions also generate temperature differences that become detectable at specific times of day. By analysing these subtle variations, researchers can identify areas with archaeological potential, which must then be investigated on the ground. Parcak herself insists that these tools do not replace excavation, but rather help to guide and focus archaeological fieldwork.

From isolated sites to landscape-scale analysis

The ability to analyse entire regions rather than just specific sites is one of the main contributions of this methodology. One of the best-known examples is the work carried out at Tanis, an ancient Egyptian city located in the northeastern Nile Delta. Although the site had been known for decades, satellite imagery helped researchers reconstruct parts of its buried urban layout, revealing streets, structures and occupation zones hidden beneath sediment and modern agricultural land.

The value of this type of research lies in understanding how ancient urban and agricultural landscapes were organised on a large scale. Parcak applied this same approach to the study of the funerary complexes and tombs of El-Lisht, one of the principal centres of Egypt’s Middle Kingdom, as well as to Petra in Jordan. There, she identified a monumental structure that had gone unnoticed despite Petra being one of the most intensively studied archaeological sites in the world.

This shift in perspective has influenced other projects around the world. In Guatemala, the Pacunam LiDAR Initiative, involving the Polytechnic University of Valencia in Spain and Tulane University in the US, identified thousands of Maya structures concealed beneath the dense jungle canopy, including elevated roadways and agricultural terraces.

In Cambodia, a combination of satellite imagery, radar, and large-scale LiDAR surveys confirmed the existence of an extensive urban network beneath the forests surrounding Angkor Wat. In the United Kingdom, the Stonehenge Hidden Landscapes project used ground-penetrating radar and remote sensing to detect prehistoric monuments buried around the megalithic complex.

In each of these cases, archaeology has moved beyond the study of isolated monuments to examine entire landscapes and the relationships between settlements, infrastructure, and the natural environment.

Sandra Angel Gavia, Gerente Calidad, Medio Ambiente y Energía Chile, Germán Silva Higuera, Subgerente Corporativo de Innovación, y Luis Shuffer Mendoza, Jefe General de Terreno, nos explican en el vídeo que acompaña este contenido cómo funciona la industrialización de la construcción, que permite entregar unidades modulares completas, listas para su instalación, con toda la ingeniería y diseño necesarios.

Gracias a este método, la fabricación, el transporte y el conexionado son más rápidos y eficientes. Hasta la fecha, ya se ha instalado el 75% de los 1.000 baños previstos mientras que otros 300 módulos se encuentran en proceso de terminación y montaje.

Beneficios frente a la construcción convencional

Los baños prefabricados ofrecen ventajas clave respecto a la construcción tradicional in situ:

1. Eficiencia en tiempos de ejecución: se fabrican en paralelo al avance de la obra, reduciendo plazos globales.
2. Control de calidad: al producirse en ambientes controlados, se asegura mayor precisión y acabado.
3. Circularidad: se minimiza el desperdicio de materiales, se optimizan recursos y se reduce la generación de residuos.

Próximos desarrollos

Los baños prefabricados son sólo el inicio. Descubre en este vídeo cómo la prefabricación está transformando la construcción en Chile y generando un impacto positivo en tiempos, calidad y circularidad. 

At Sacyr, we believe that every project we undertake carries a responsibility to the environment, our team, and our entire value chain. While we build infrastructure, our primary focus is working with and for people. Therefore, fostering fair, safe, and respectful workplaces is central to how we drive growth.

In this context, the SA8000 standard has become vital. This international standard ensures our operations align with rigorous social criteria, with a steadfast focus on human rights in the workplace. It is not merely about compliance, but about embedding these principles into our corporate culture and daily practices.

From Commitment to Action

To achieve this, we translate these principles into concrete actions within our daily operations. Our Human Rights and Community Relations Policy is publicly available and applies to everyone across our organization, as well as our stakeholders.

Furthermore, we foster a culture rooted in active listening. To support this, we provide confidential channels that allow anyone to raise concerns safely. This is complemented by our continuous reinforcement of occupational health and safety, with dedicated committees at every construction site to help protect our teams.

The Role of the Social Performance Team

Within this framework, the Social Performance Team (SPT) plays a pivotal role. Comprising representatives from both management and the workforce, it serves as a forum for dialogue and collaboration.

Its mission is to bridge gaps, facilitate open communication, and identify areas for improvement. Ultimately, it ensures that the standard's principles translate from theory into practice across our construction sites and workplaces every day.

Assessment and Continuous Improvement

All of these efforts are subject to ongoing review. Our construction division in Spain is SA8000-certified, having successfully passed an independent audit that verified compliance with all requirements for the third consecutive year.

These assessments involve private and confidential interviews with employees and suppliers. This provides first-hand insight into how these commitments are implemented on the ground, enabling us to drive continuous improvement.

A Global Commitment

Furthermore, this approach aligns with our commitment to international standards such as the Universal Declaration of Human Rights, the OECD Guidelines, and the International Labour Organisation (ILO) principles.

SA8000 certification is not a destination, but a tool for ongoing progress. It drives us to strengthen a working model that puts people first. At Sacyr, we believe that only by prioritizing respect, equality, and safety can we deliver a truly positive and sustainable impact.

This project demonstrates how cross-sector innovation and collaboration can reduce emissions, optimize costs, and accelerate sustainability.

While steel production and water desalination might appear to be unrelated activities, the Sohar industrial hub has demonstrated their potential for synergy.

The Sohar 4 IWP plant, managed by Sacyr Water, requires CO₂ to stabilize the pH of the treated water, prevent scaling in distribution networks, and ensure safe water suitable for human, agricultural, and industrial applications.

Traditionally, CO₂ is sourced from external suppliers, incurring high economic and energy costs. The presence of large industrial emitters within the hub itself presented an opportunity for a more efficient solution: capturing CO₂ at its source and reusing it locally.

Industrial Symbiosis: Environmental and Economic Impact

This initiative, spearheaded by Abdullah Al Sadi, Operations Service Director at the Sohar plant, transforms an industrial emission into a key resource for water treatment. This model of industrial symbiosis reduces emissions at their source, enhances the quality of the treated water, and optimizes operating costs. 

"The use of captured CO₂ allows us to improve water quality while reducing emissions directly at their source," explains Al Sadi.

The project received Sacyr's 2025 Natural Innovators Award, in the 'We Are Excellence' category.

Operational Efficiency

The Sohar 4 IWP plant produces approximately 250,000 m³ of water daily. It currently consumes around seven tons of CO₂ per day, with projections to reach 12 tons in the coming years.

Local CO₂ capture virtually eliminates logistics costs and reduces CO₂ costs by approximately 40%.

Reduced Carbon Footprint and Chemical Usage

While the process does not reduce the energy required for desalination, it significantly lowers the carbon footprint of the treated water by substituting externally sourced fossil-based CO₂ with CO₂ captured from local industry.

Furthermore, the use of captured CO₂ reduces the need for other chemicals like hydrated lime, carbonate, or sodium bicarbonate, and optimizes chlorine usage. These benefits collectively lead to a lower environmental impact, reduced operating costs, and more efficient water chemistry.

This approach also provides access to regulatory advantages, fosters greater social acceptance, and strengthens our competitive position in markets with increasing demands for sustainability.

Looking to the Future

After two years of development, the project is now entering a new stage focused on consolidating pilots, obtaining permits, and scaling up to commercial solutions that can be replicated in other industrial environments.

This is another example of how innovation and cross-sector collaboration can transform significant environmental challenges into shared opportunities.

Nitrogen pollution in wastewater is an increasingly prevalent environmental challenge due to industrial, urban, and agricultural activities. Conventional nitrogen removal processes require intensive energy and a sufficient amount of organic matter that is not always available. 

To improve this process and make it more efficient, we are innovating with the Denitox project, which we are developing together with the University of Granada.

"With Denitox, we managed to reduce nitrogen by up to 80% and save energy by up to 50%," explains Elena Campos, head of Technical Support for Sacyr Agua's Treatment Area.

The nitrogen present in surface water bodies can promote uncontrolled algae growth, which can lead to high fish mortality, as has happened in the Mar Menor.

More restrictive European directive

The new European Wastewater Treatment Directive (TARU) drastically reduces the limits of nitrogen in discharge, which in many cases implies a real technological challenge. 

The runoff stream in plants with anaerobic sludge digestion can reach up to 20% of the total nitrogen load that reaches the plant and needs to be retreated after removal. Hence the importance of treating these return streams that have a high nitrogen content, but a low organic matter content. 

With our Denitox technology we can achieve lower nitrogen emissions in the discharge, with high polluting potential, economic savings and the reduction of greenhouse gas emissions.

Pilot test

"We have carried out a pilot test in the Guadalajara treatment plant, which was applied to the return stream of the sludge line, which has a lot of nitrogen. If wastewater normally has between 60 and 80 mg per liter, that stream has 500-1,000 mg per liter. In this study, which was carried out with real water and variable conditions, an 80% reduction was achieved in a stable way," explains Elena.

"Now, the main challenge is to maintain these high efficiencies at room temperature and shorter hydraulic retention times. If we manage to bring it to an industrial scale, Denitox would be a competitive solution for wastewater treatment applicable in many treatment plants to meet nitrogen removal targets," concludes Elena Campos.

Before this test, a stopover was made in the laboratory at the University of Granada, with which we have developed this technology.

"We have optimized the operating conditions, but we need to scale up to a larger size and see how to control the conditions well.

International award in Saudi Arabia

Recently, the Denitox project has won the Global Prize for Innovation in Water (GPIW), organized by the Saudi Water Agency, in the Sustainable Water Production and Environmental Conservation category.

This category values the balance in water supply with the protection of the ecosystem and the reduction of emissions.

Jesús Alcanda

Sacyr Energy

Public opinion naively believes that Spanish forests are neither born, nor do they grow or die: they simply remain. The public assumes forests require no human intervention to ensure their continuity, and that they will always be there, unless they are devoured by summer wildfires.

In the Iberian Peninsula, Forestry—the science dealing with the care and management of forests—is older than the Emperor Trajan. This was documented in the first century by the writer Columella, from Cádiz, in both De Re Rustica ("The Twelve Books of Agriculture") and De Arboribus ("On Trees").

Just as Agronomy is the science of the agro (the field), Forestry (traditionally termed Dasonomy) is the science of the daso (the forest).

Like almost all sciences, forestry has steadily expanded its boundaries of certainty, branching into various specialties. Among the disciplines that make up forest science, two—Silviculture and Forest Management (traditionally known as Dasocracy)—underwent a major systematization of knowledge from the mid-19th century to the late 20th century. It is precisely these two disciplines that are responsible for ensuring that forests successfully regenerate.

Forest Management (Dasocracy, from daso, forest, and cracy, power in the sense of governance or order) is the discipline that deals with the regulation of forest lands. It consists of a suite of techniques designed to organize the forest to ensure its long-term succession.

The analytical techniques of Forest Management guide the forest toward a balanced population pyramid. This means achieving a structure without gaps or inversions, containing all tree age classes distributed in a way that demonstrates equilibrium, proving that the forest is sustainably managed.

The other pillar of forestry, Silviculture, is to the forest what agriculture is to the field: a set of treatments and interventions that ensure maximum vitality, appropriate density, and the protection of the forest stand.

Each age class (e.g., 25 to 50 years) must be represented by a specific number of trees within a given area. In other words, for every age class, there is an optimal canopy density—represented by a range of trees per hectare—which silvicultural practices must achieve so that the trees grow with the greatest possible strength and vigor.

What does Forest Management do to secure the regeneration of the forest shown in Figure 1?

First, it divides the forest land into compartments (or periodic blocks), one for each distinct age class. The compartment containing the oldest age class (trees over 100 years old) is set aside as a biodiversity conservation zone.

A total renewal plan is then applied to the other four compartments, to be executed over the next 100 years. To achieve this, every 25 years, the oldest compartment (aged 75 to 100 years) is designated as the regeneration block.

This means that for 25 years, regeneration cuts will be carried out in this compartment using the "uniform shelterwood system" to open gaps in the canopy, allowing new saplings (the offspring of the surrounding trees) to establish themselves and grow.

It is called a uniform shelterwood system because, over a 25-year period, successive, uniform cuts are made to gradually open up clearings in the regeneration compartment. Meanwhile, in the other three compartments, thinning cuts are applied to adjust tree density to their age. This maintains their vigor and strength, preventing them from growing in overstocked conditions that would significantly weaken them.

After these first 25 years, the regeneration compartment will contain young trees aged between 0 and 25 years (at which point the stand is considered regenerated), while the remaining compartments will have aged by 25 years.

This shelterwood harvesting process is repeated every 25 years in whichever compartment is the oldest at the time, until regeneration cuts have been applied to all four compartments, as shown in the following diagrams, where the first frame represents the "parent forest":
 
  
 

  
After 100 years, a completely new forest has been established—a descendant of the parent forest shown in the first frame. This is achieved by applying uniform shelterwood regeneration cuts over 25 years in each compartment, while managing the density of the remaining compartments through thinning.

The timber harvested from each of these cuts generates enough revenue to finance subsequent operations, thereby self-funding the forest's regeneration plan.

It is highly inadvisable to apply regeneration cuts to excessively old forest stands. Extremely old trees have a significantly reduced capacity to produce seeds, and the germination rate of those seeds also declines. Leaving the future of a forest in the hands of overmature stands is highly reckless.

When well-meaning individuals oppose the harvesting of trees in a managed forest, in the vast majority of cases, they are unwittingly contributing to the amputation of that forest's future. They are also driving its abandonment—the precursor to devastating wildfires, which are the particular hell of Spanish forests.

But as we all know, the road to hell is paved with good intentions.

Sacyr Maintenance has started deploying a robotic quadruped to inspect the extensive, kilometer-long galleries deep inside dams. These critical hydraulic structures often have thick concrete walls, which severely restrict external connectivity and make traditional inspections challenging. An autonomous robot, therefore, offers an ideal solution. This advanced machine assists professionals with routine checks and can identify potential hazards like dangerous gases or excessive moisture before they become critical.

The Duero Hydrographic Confederation originally proposed this autonomous robotic inspection project. They specifically suggested deploying the quadruped at the Pontón Alto dam, situated between Segovia and La Granja.

This system significantly enhances both inspector health and safety, alongside boosting operational efficiency by allowing for more frequent inspections.
Jose Luis Barragán, COEX Dam Manager for Zone F of the Duero Hydrographic Confederation (where Sacyr Maintenance operates), explains: "The galleries the robot explores contain vital components such as water supply valves and sluice gates. While existing sensors monitor parameters like pressure, flow, and displacement, our goal is for the robot to photograph specific, predetermined points."

"These different gallery levels are connected by stairways, enabling UGV (Unmanned Ground Vehicle) robots to move freely between them for thorough inspections. This represents our first time incorporating such advanced technology into dam conservation," Barragán adds.
 

The challenge is in the location 

The immediate challenge lies in implementing an effective robot localization system, particularly since GPS signals are unreliable deep inside the dam. To overcome this, Sacyr Maintenance is exploring solutions like creating a detailed 3D map or developing a digital twin of the galleries.

"In the future, the robot could be trained to do more than just capture images. It could also extract and analyze data, proactively preventing issues like cracks, moisture ingress, and excessive seepage," the expert suggests.

Initial navigation tests have already been successfully conducted, with ongoing development planned for the coming months.

MARÍA GÓMEZ BRAVO | Tungsteno

Clinging to a granite wall requires understanding the language of the rock. Since the Middle Ages, architecture has sought solutions that would allow people to inhabit the most extreme terrains, defying gravity as if floating above the void. The Hanging Houses of Cuenca, built in the 15th century, the monasteries of Meteora in Greece, suspended on near-vertical rock pillars, or contemporary designs such as Australia’s Cliff House, are structures that share the same idea: to build right on the boundary between solid ground and empty space.

Cuenca: Conquering Airspace

During the 15th century, the town of Cuenca established itself within the Kingdom of Castile as a strategic stronghold and the region’s economic hub. This growth created the need to accommodate an expanding population beyond the medieval walled fortress overlooking the gorges of the Júcar and Huécar rivers. The scarcity of available land led to the design of the Hanging Houses, a conquest of the void yet independent of it.

The construction relied on complex structural systems using cantilevered beams (known as almojayas) supported by the interior walls. These systems counterbalanced the weight of the overhanging balconies with the floor structure of the building’s lower level. The complex, which can be admired from across the river, was recognised as part of the historic walled town of Cuenca, which was declared a UNESCO World Heritage Site in 1996.

Meteora: Balance as Reinforcement

The Orthodox monasteries of Meteora (Greece) faced a different challenge: maintaining balance atop porous rock pinnacles, rising almost vertically above the plains near Kalambaka in Thessalian. As in Cuenca, the solutions employed reflected an adaptation to the environment.

The Orthodox-Byzantine monasteries of Meteora are built so that their weight distribution prevents the sandstone pinnacles on which they are perched from collapsing. Credit: Walter Weinberg / 500px/Getty Images

These towering pillars of sandstone and conglomerate, some of which reach up to 600 metres, were chosen by the Orthodox-Byzantine monks in the 14^th century as sites for monasteries, offering refuge from Ottoman attacks. The unique setting, which translates from the Greek Μετέωρα as “suspended in the air”, was ideal for solitary spiritual practice and could only be accessed by long ladders or rope nets hoisted by pulleys.

In this feat of medieval engineering, the monks exploited natural cracks in the rock to wedge in wooden pegs and erect temporary scaffolding. The rock itself was used to build the walls and carve cisterns for collecting rainwater.

The weight distribution of the monasteries is typically concentrated at the centre of the pinnacle, which prevents the stone column from collapsing. The structure itself acts as a compression plug, sealing fissures in the porous sandstone and preventing them from expanding due to water infiltration.

The Evolution of the Cantilever: From Wood to Steel

These rock-based construction techniques have evolved into other extreme projects that seek minimal impact on the landscape. One such example is the houses in the Wangxian Valley in China, an example of rural regeneration where architecture revives the traditional aesthetics of the Xian ethnic group through cutting-edge engineering.

The dwellings are suspended from granite walls using cantilever principles, but rather than wooden beams, they employ concealed steel structures and high-strength bolts anchored into the rock. The same technical approach is employed in the as-yet-unbuilt Modscape Cliff House in Australia, a conceptual project designed to hang over a precipice on the Victorian coast.

The dwellings in China's Wangxian Valley are anchored to the rock using steel structures and high-strength bolts. Credit: Jaclyne Ortiz/Istockphoto

The proposed design consists of five modular units anchored to the rock with high-strength steel fixings, mimicking the way barnacles attach themselves to a ship’s hull. The stability of the structure is determined by the controlling of loads and the torsion of the structural elements, a technical challenge with a centuries-long history that can now be addressed through digital simulations and high-strength materials.

The desire to float above the landscape is not new. In the late 1960s, the modernist architect Harry Weese already defied gravity with the Shadowcliff, a glass and steel structure over Lake Michigan in Ellison Bay, Wisconsin. This demonstrated that steel could make it possible to inhabit the abyss without the need for massive foundations.

What once arose from defensive or spiritual needs in medieval times has evolved into extreme architectural solutions that test our ability to inhabit places where we were never meant to be.

Tungsteno es un laboratorio periodístico que explora la esencia de la innovación.

Six Sacyr professionals participated in an international volunteer program organized by the Sacyr Foundation in collaboration with the NGO UPlanet.

Paco Molina, Iván Roselló, Camila Quintín, Eva Abad, Lucía Cecilia, and Ana Grande spent a week in Bir Moghrein, an isolated village in northern Mauritania. The expedition also included Rubén Fernández, Ana Grande's son, along with a group of 30 healthcare professionals from HumanCoop, four members of UPlanet, and a professional from Viamed, Rodrigo Morilla, a former Sacyr colleague.

This marks the second edition of the volunteer program in Mauritania, which aims for Sacyr professionals to help repair and develop infrastructure that impacts the lives of the local population.

Among the projects they collaborated on, a highlight was the repair of deficiencies in the village's desalination plant to improve water production and quality. Additionally, the necessary technical documentation was created for the installation of a new containerized desalination plant, which is scheduled to arrive in the summer.

The electrical system of the health center was also renovated, a project to install new latrines in the primary school was developed, and progress was made on a one-hectare garden project to provide food for the population and create employment for women.

Finally, an entrepreneurship workshop was organized to boost the local economy among women.

A tough but rewarding experience

"On a personal level, it has been an incredible experience; it grounds you and gives you a lot of perspective on life. Professionally, it has been rewarding to be able to make my small contribution through this wonderful profession," explains Camila Quintín (Sacyr Engineering and Infrastructure).

Paco Molina and Iván Roselló, both from Sacyr Water, collaborated on improving the desalination plant's facilities. They adjusted water quality by implementing a mixing system with filtered water to extend the life of the membranes. They also created a bypass for the filter backwash water.

Paco Molina states that it is a trip "worth repeating." "It has been a tough yet kind, disheartening yet enriching, selfish yet selfless experience – a mix of contrasting feelings, but always with a positive balance," he adds.

"We have bridged gaps through effort and collaboration," affirms Iván Roselló.

"Our group created a balanced ecosystem in a remote and inhospitable place. A reality check that puts my concept of 'life' into perspective," says Eva Abad (Sacyr Proyecta).

Ana Grande (Sacyr Holding) emphasizes that this volunteering experience is a "challenge overcome." "I applied engineering outside of my comfort zone, engaged in teamwork, and gained real learning. It has been an experience that adds value professionally and personally, thanks to the people with whom I shared this adventure," remarks Ana.

"It has been a tough but very rewarding experience at the same time. Helping these people who have so little gives you another perspective on life and what is truly important, which is helping each other. I value the human warmth of my colleagues," explains Lucía Cecilia (Sacyr Holding).

Rubén Fernández, in charge of the electrical tasks, stated that "the lack of technical materials made work difficult at the clinic, but with effort and improvisation, we managed to get our job done." He adds, "It has been a different and tough experience, but I have learned so much about how fortunate we are to live in a country like ours and the ease we have in Europe of drinking tap water and finding whatever you need in any store."

Collaboration with UPlanet

The collaboration between the Sacyr Foundation and UPlanet is fundamental for integrating infrastructure in this underdeveloped region, isolated by a vast desert expanse. UPlanet, in turn, collaborates with HumanCoop, which organizes medical-surgical missions to the country, thereby creating synergies in organizing all logistics.

The next initiative we will collaborate on will be the installation of a new portable containerized desalination plant, which will arrive in Bir Moghrein in the summer.

"Our collaboration with UPlanet helps us reach these remote areas, where, thanks to our help, they can count on experts in infrastructure and water who collaborate to improve the facilities of these communities," explains Pedro Alonso, Director of the Sacyr Foundation.

"International volunteer programs help our professionals step outside their usual scope of work and grow as individuals," he explains.

"At UPlanet, we believe that community development hinges on improving basic infrastructure, which allows for laying the foundations of sustainable development. Thanks to the collaboration and contribution of the Sacyr Foundation, the actions carried out in agriculture, water, and sanitation have been a success. They have immeasurable value," explains Matías Fernández, Presidente of UPlanet, a former colleague from Sacyr Water, and coordinator of the field mission conducted in Bir Moghrein.

The 2021 eruption of the Tajogaite volcano in La Palma (Canary Islands) buried the LP-2 road while it was undergoing construction. We are currently rebuilding the section between kilometers 40 and 43, contending with the high temperatures that still persist within the lava field.

“Constructing this new road across the lava field necessitates a thorough assessment of the ground's thermal conditions, as volcanic lava flows can retain high temperatures for many years,” explains Juan Antonio Romero, Head of Topography at Sacyr Engineering in La Palma.

We have addressed this challenge by deploying drones equipped with infrared thermographic cameras for the capture, analysis, and thermal modeling of the affected terrain.

 

This technology enables us to identify areas with significant thermal activity, evaluate the technical feasibility of the proposed route, and provide recommendations to ensure safe operations for our professionals and partners.

Furthermore, this detailed analysis helps anticipate potential impacts on the road pavement structure and bituminous mixtures, as thermal variations can alter their cohesion, stiffness, and durability. This, in turn, informs the design and construction decisions for the future pavement.

This project is spearheaded by the Canary Islands Ministry of Public Works, which awarded the contract to the JV TAJUYA joint venture (comprising Sacyr Engineering and Infrastructure, Traysesa, Herquipalma, and Los Volcanes). The project is slated for completion in 2028.
 

Thermal Radiation Measurement

Infrared thermography is a remote sensing technique that detects thermal radiation emitted by objects based on their surface temperature. In the geotechnical field, this tool has proven to be an effective method for:

•    Identifying areas of residual volcanic activity.
•    Detecting active fractures and gas emissions.
•    Analyzing cooling processes in lava flows.
•    Evaluating the thermal stability of ground for civil engineering projects.

“Through the acquisition and processing of infrared images, we have generated georeferenced heat maps and graphs that illustrate the thermal evolution. The DJI MATRICE 350 RTK drone, equipped with a camera, can detect temperatures ranging from 0 to 550 degrees Celsius,” explains Juan Antonio Romero.

“This undertaking combines advanced technologies in remote sensing, thermal photogrammetry, and geospatial analysis. As a result, we enhance the road's quality and, crucially, improve site safety and occupational health,” he concludes.

At Sacyr Water, we have a new system trained with artificial intelligence to detect damage in its collector networks. 
"We believe that AI can achieve very low error rate functionality by training a model that learns from common defects detected by the human eye, such as cracks, fissures, and blockages in the sewerage network.

This Machine Learning model helps us reduce the error rate in detecting these common defects. Additionally, Artificial Intelligence has been implemented to interpret text and generate final reports", explains Miguel Cebrián, head of digital transformation at Sacyr Water.

VIDIA is an asset intelligence platform developed by Sacyr for critical sanitation infrastructure management. 

This system transforms the traditional network inspection process into an automated, data-driven workflow. It doesn't just identify damage; it classifies it according to standardized typologies.

VIDIA utilizes generative artificial intelligence, advanced analytics, and integrated visualization, converting raw data into strategic information for decision-making. It is a tool that unifies everything: people, processes, and technology, providing a 360º view of the service. 

"First, camera footage is captured, which can be done via a drone or a robot within the sewage network. Then, this video is fed into our VIDIA system which, thanks to ML technologies, identifies images, and with Generative AI, analyzes texts and automatically generates reports," states Miguel Cebrián.

Furthermore, VIDIA is integrated with the GIS system. This means all alerts are georeferenced on a city map, allowing for the prioritization of actions in strategic or sensitive areas.

This machine learning model, trained with generative AI, has been jointly developed by Sacyr Water's technical department and the company's IT department. 

VIDIA differs from all similar systems in the water sector because it automates the entire workflow. It not only identifies damage but also contextualizes it: classifying it according to standardized typologies and precisely geolocating it within the collector.

VIDIA is positioned as a key tool to anticipate incidents, reduce operational costs, and ensure service continuity. 

"Digital transformation in sewage network management is no longer an option, but a necessity. This tool transforms a traditionally slow and costly process into an automated, intelligent, and results-oriented workflow", concludes Cebrián.

Superblocks are making their way into our urban layouts. They go beyond the traditional concept of blocks to configure larger spaces in which traffic decreases and improves the integration of leisure, green areas, and residential buildings.

"Urban superblocks reorganize the urban fabric to prioritize pedestrians," says Gema Ortiz, Innovation project manager at Sacyr and head of Sustain, a superblock project in the center of Seville (Spain).

Our site, Las Setas de Sevilla, participates in Sustain together with a consortium of companies and entities. In a city as touristy as the Andalusian capital, this project aims to improve the experience of visitors and citizens of Seville.

"We seek a positive social impact and we rely on cutting-edge technologies, such as digital twins and artificial intelligence," explains Leticia Franco, coordinator of Las Setas de Sevilla.

Sustain is funded with €1.8 million by the "Science and Innovation Missions 2024" Call, promoted by the Center for Technological Development and Innovation, with Next Generation funds from the European Union, within the Recovery, Transformation and Resilience Plan.

It is led by Inycom, and together with Las Setas de Sevilla, Cemosa, Buchanan and Simetría Innovación are participating.

Sustain addresses digitalization, sustainability, resilience and social impact in urban environments. "We promote a significant reduction in the carbon footprint, an improvement in energy efficiency and environmental quality and an optimization of urban mobility. In short, the creation of healthier and more sustainable environments," explains Gema Ortiz.

To achieve these objectives, an integrated management platform is being developed that, through the use of digital twins and artificial intelligence algorithms, allows the design and optimization of superblocks in all their constituent elements: building, mobility and redevelopment.

The platform simulates behaviors and makes decisions based on data from different sources, in order to reduce risks, improve participation, and continuously adapt the design to maximize social, environmental, and economic benefits.

Thanks to this technology, Las Setas de Sevilla will be able to improve infrastructure management, security, user experience and maintenance.

"Together with the ITA Technology Center, we have developed a digital twin that will allow us to identify behavioral patterns in Las Setas visitors through the use of various sources, cameras and mobile data, among others. In addition, we will predict behavior in future scenarios and, based on this, we will be able to deploy our management strategy", summarizes Leticia Franco.

This ambitious Barcelona Metro Line 8 extension will introduce four kilometers of new track, three new stations (Gràcia, Clínic, and Francesc Macià), and include a significant upgrade to the existing Espanya station. The Joint Venture (JV) awarded the project comprises Sacyr (27.5%), Ferrovial (27.5%), Copcisa (22.5%), and Copisa (22.5%).

The TBM, a critical component for this expansion, is presently in Sant Boi, where it's undergoing its conclusive tests.
“We are conducting thorough inspections, testing all components, software, automation, and mechanical functions to guarantee flawless operation before relocating it to the Gran Vía launching shaft,” explains Toni Julià, the JV's Construction Manager.

Later this month, the TBM's various components will commence their transfer to the launching shaft, marking the precise location where excavation will begin. This powerful machine is expected to remove over 300,000 cubic meters of earth.

The excavated material will be transported from Joan Miró Park via an auxiliary micro-tunnel constructed beneath Llançà Street. From there, a dedicated conveyor belt system will transfer the spoil to waiting trucks for disposal at a landfill.

“The launching shaft is progressing very well: the front section is being prepared with the base slab for TBM assembly, while the rear is being configured for its connection with the micro-tunnel. We are also erecting an acoustic enclosure to mitigate noise during the boring operations,” Juliá adds.

Constructing Record-Breaking 82-Meter Diaphragm Walls

Even as the TBM assembly advances, other critical construction activities are in full swing.

At the Hospital Clínic and Francesc Macià station sites, hydrofraise trench cutters are actively constructing diaphragm walls that will reach an impressive depth of 82 meters. These are set to be the deepest ever built in Spain.

These robust diaphragm walls are essential; they will enable the safe excavation of the shafts through which the TBM will pass and, subsequently, facilitate the construction of the underground caverns designed to house the station platforms.

Key Highlights of this Major Infrastructure Project

“With an anticipated 19 million annual users, this project represents one of the most socially and economically beneficial undertakings within the Generalitat's Infrastructure Master Plan,” Toni Julià emphasizes.

The L8 extension will seamlessly connect Barcelona's two primary railway networks—Baix Llobregat and Vallès—managed by FGC. This integration is poised to significantly enhance intermodality and overall city-wide mobility. The project carries a budget of €322 million and is scheduled for completion within 61 months.

Understanding the seabed is key before initiating any marine construction project. Bathymetry, or detailed seabed mapping, consistently faces numerous challenges, including the inherent conditions of the sea itself.

These challenges have arisen during the Central Pier Extension, Phase 2, project at the Port of Bilbao. There, we conducted verification tests to enable operations with easily transportable semi-submersible uncrewed vehicles.

"We have innovated by installing a multibeam echosounder and a side-scan sonar on these units. Using acoustic waves, we acquire seabed elevation data," explains Alfredo Pérez, Head of Marine Works at Sacyr Engineering and Infrastructure’s Technical Services Department. Pérez was recently honored with the Natural Innovators 2025 award, a Sacyr internal program for the promotion and advancement of innovation.

"Thanks to this drone, we reduce CO2 emissions and enhance operational capability in the most unfavorable weather conditions," he explains.
"Tests have been conducted both in the open sea and within the port basin. This allows for a more thorough evaluation of the characteristics of this semi-submersible unit and enables a comparison with conventional methods," Alfredo Pérez adds.

Acoustic probes are the only ones that propagate effectively in turbid aquatic environments. This high-frequency echosounder generates a conical beam, providing a data point cloud with far more comprehensive seabed information than traditional single-beam echosounders. This point cloud is then used for data processing, interpolation, and noise reduction, ultimately rendered as contour maps for detailed seabed interpretation.

Bathymetric surveys performed with this method are compared with those obtained by conventional means, and an analysis is conducted to determine if the tolerances between both datasets are within acceptable values.

The echosounder used in Bilbao offers a scan that allows for real-time visualization of the seabed. It provides insights into the terrain's hardness and roughness and performs side scans for object detection. Its measurements can be taken in environments up to four times more challenging than those supported by conventional methods.

"In the future, our goal is to expand the inner data cone to 160 degrees. We also plan to install an antenna on the echosounder to use an airborne bathymetric lidar, which would provide both terrestrial and marine data in a single operation. This way, we will have complete terrain profiles, overlapping both the marine and terrestrial sections," says Alfredo.

ISABEL RUBIO ARROYO | Tungsteno

In 1968, Windhoek, Namibia, became the first city in the world to use recycled drinking water. Today, its example inspires other places: the Orange County Water District in California supplies more than a million people with safe recycled water, and Singapore, through its NEWater plant, produces recycled water for both industrial and household use. We explore the projects and processes that give every drop of water a “second life.”

How Namibia turns wastewater into drinking water

Namibia is one of the most arid countries in sub-Saharan Africa, and Windhoek sits on a plateau where evaporation is extreme: 83% of the rain that falls disappears into the air. The city lacks nearby perennial rivers and depends on water sources that fluctuate dramatically with the climate. Faced with chronic shortages and severe rationing in the late 1950s, the city had to look for innovative solutions.

In 1968, the Goreangab Water Reclamation Plant was established, using direct potable reuse. In other words, treated wastewater is fed directly back into the supply network without passing through a natural “buffer” such as a river or lake. Windhoek’s system is like an obstacle course for water: it must pass through multiple filters and treatment stages until it becomes completely safe to drink.

To keep pace with rapid population growth and rising demand, a new treatment plant was built in 2002. Today, the Windhoek system is a global benchmark and an example of sustainable water management, visited by experts from around the world. The plant produces up to 21 million litres of potable water per day. On average, the city’s drinking water contains between 20% and 25% recycled water. During periods of extreme drought, this source can provide nearly a third of the total supply.

Namibia has a pioneering project to convert wastewater into drinking water. Credit: DW News

A Giant in Drinking Water Recycling in California

There are other notable examples of water recycling. Orange County operates the Groundwater Replenishment System (GWRS) in California, recognised as one of the world’s largest water purification systems for drinking water reuse. Unlike Windhoek, which uses direct potable water reuse (to the tap), Orange County uses indirect potable reuse. This means that once the wastewater is purified, it is not sent directly to homes. Instead, it is injected or percolated into the county’s groundwater basins, where it mixes with the natural water supply before being extracted again for human consumption.

The system can produce up to 130 million gallons per day (about 492,000 cubic metres), enough to meet the needs of nearly one million residents, according to the Orange County Water District. This system supplies approximately 35% of the region’s total water demand and reduces dependence on imported water from the Colorado River or the Sacramento–San Joaquin Delta in Northern California.

This is one of the world’s largest indirect potable water reuse plants. Credit: Orange County Water District

The Water Revolution in Singapore

Singapore is also a global leader in water management. As an island nation with limited freshwater resources and little space for reservoirs, it faces one of the highest levels of water stress in the world. The NEWater process converts wastewater into ultra-pure potable water in three key stages: first, microfiltration and ultrafiltration remove microscopic particles and bacteria; next, reverse osmosis captures viruses, heavy metals, and chemical contaminants; and finally, ultraviolet disinfection eliminates any remaining microorganisms.

Singapore strives to manage its water safely. Credit: DW Planet A

At the heart of the system lies the Changi Water Reclamation Plant, which can treat up to 900 million litres of water per day. Because of the island’s limited space, much of the system operates up to 25 storeys underground, through a complex network of tunnels and tanks. The system relies on indirect potable reuse. Although the water is technically potable after treatment, most of it is used for industrial purposes—especially in the manufacture of microchips, which require extremely pure water—and for cooling systems. Only a small amount is pumped into reservoirs, where it mixes with raw water and undergoes further treatment in conventional plants before reaching homes.

Tungsten is a journalistic laboratory that explores the essence of innovation.

ISABEL RUBIO ARROYO | Tungsteno

Barbara Jatta, the first-ever female director of the Vatican Museums in over five centuries, is responsible for safeguarding and restoring some of the Vatican’s most inaccessible spaces: sealed chambers, hidden storage rooms, and restricted areas where manuscripts, frescoes, and objects too fragile to be displayed are conserved. Under her supervision, specialised teams labour quietly, employing techniques ranging from traditional craftsmanship to the use of lasers, 3D scanning, and advanced conservation systems. Jatta safeguards a heritage that few ever see, yet one that underpins the world's most significant artistic and religious history.

Breaking Ceilings: The Story of Barbara Jatta

In 2017, Barbara Jatta made history by becoming the first woman to lead the Vatican Museums in their 516-year history. Given the site’s immense artistic importance, some say she shattered not merely a glass ceiling, but a “frescoed ceiling.” Born in Rome and academically trained in Art History, Jatta had spent more than two decades at the Vatican Apostolic Library before assuming what is widely regarded as one of the most coveted positions in the art world.

Today, she oversees a treasure trove of more than 200,000 works of art, spread across 11 kilometres of galleries, and oversees seven restoration laboratories. Under her leadership, the museums are not only preserved but increasingly digitised: virtual tours and online catalogues allow the Vatican's artistic heritage to reach audiences worldwide. With every decision about what to exhibit or what to keep secret, Jatta breathes life into a legacy that is both cultural and spiritual.

Jatta looks back on her journey at the helm of a collection of more than 200,000 works of art. Credit: EWTN

What Remains Unseen in the Vatican Museums

The proportion of works on display compared with those kept in storage varies depending on the type of art. “If we look at the percentage of what is on display and what is in [storage], it is amazing. Certain collections have only 1% on display,” she explained in an interview. In the case of painting and contemporary art collections, she estimates that the ratio is “25% on display and 75% in storage.” The institution seeks to “rotate some collections to show them better,” especially those that are easier to move, such as contemporary art and paintings.

Although Jatta is responsible for safeguarding monumental masterpieces such as the Sistine Chapel, her favourite work is a small painting of the Virgin and Child by Fra Angelico, located in Room IV of the Pinacoteca, which often goes unnoticed by many visitors. One of her preferred locations within the entire complex is the Belvedere Terrace. Designed by Bramante in the 16th century, this area is closed to the public and offers a view over Vatican City.

The Virgin and Child between Saint Dominic and Saint Catherine of Alexandria. Credit: Fra Angelico / Vatican Museums Pinacoteca

Within the complex, Jatta has experienced many unique moments. She recalls walking through the empty galleries during the pandemic lockdown, accompanied only by a small number of guards. She describes the experience as “terrifying” and “magical” at the same time, like being in a ghost town. During that period, the institution faced a profound financial crisis, as the Vatican Museums—unlike other large museums—rely exclusively on ticket sales. After a year of intermittent closures, Jatta acknowledges that anxiety spread: “People around us were talking about selling our objects to survive.” She describes the institution's recovery as a “miracle” that allowed activities to resume without the need to part with its artistic heritage.

From the Vatican to the World

Today, Jatta is a member of prestigious international organisations, such as the Scientific Council of the Louvre Museum and the International Advisory Committee of the Hermitage Museum. Over the course of her career, she has received numerous distinctions, including the Order of the Star of Italy (2019), Commander of the Royal Order of the Polar Star of Sweden (2020), and the rank of Officer of the Order of Arts and Letters of France (2021).

This international recognition reflects her view of art as a spiritual bridge that unites cultures and nations. For this reason, the museums under her direction organise exchanges with countries such as China, Mexico, and Chile. Jatta describes the collections as an “invaluable heritage of creativity, civilisation, art, history, and tradition.” This richness is valued not solely for the objects themselves, but also for the devotion that ensured their preservation across the centuries.

Tungsten is a journalistic laboratory that explores the essence of innovation.

Jesús Alcanda Vergara

Energy division of Sacyr Water

It was 1991 when my friend Luis Carlos and I met at the Natural Environment Service of Zamora with José Luis Montero de Burgos (who had served for 20 years as Head of the National Reforestation Service of the Ministry of Agriculture). We were attending a meeting with the Service’s technical staff to hear the guidelines they intended to propose for a reforestation project covering 6,000 hectares devastated by fire in the Sierra de la Culebra—a project whose drafting had been entrusted to us.

Each time the Service presented an approach, Montero de Burgos, supported by decades of experience, insisted on the need to involve local people and respect their traditional practices and livelihoods. He repeated this warning again and again, responding to every new proposal put forward by the technicians.

Eventually, the discussion shifted toward what they considered to be “the problem” posed by the residents of the Sierra, which had already been proposed as a Protected Landscape.

So enthusiastic were these technicians that, with astonishing unanimity and without the slightest embarrassment, they reached an extraordinary conclusion: that what truly did not belong in the Sierra de la Culebra was the people who lived there.

They made it clear that, in order to manage this protected natural space, the local population was “excessive,” and that it should be a priority to remove as many residents as possible.

Today, 35 years later, these technicians—some of whom have since passed away—must feel satisfied. Their wishes have almost been fulfilled: the population of this Protected Landscape has been reduced by half.

Public Administrations are quick to invoke phrases such as “land management,” abstract formulas that promise what is impossible precisely because of their abstraction.

By mobilizing staff and departments around such slogans, they forget their original purpose: to administer, to serve, to allocate resources responsibly, to care for the common good. In doing so, they betray the very etymology of the word administration. Governments and their agencies—ministries, departments, councils—are meant to govern people, not merely manage things.

By replacing the verb to administer with to manage, public institutions forget their essential role: serving society. Instead, they reduce their mission to the technical control of objects and territories, detached from the people who inhabit them.

If it is already misguided to substitute administration with “management,” it is even worse to apply this logic to something as vague and complex as “territory.” This intellectual confusion becomes outright delirium when authorities decide to grant rights not to people, but to things.

To grant rights to land, rather than to human beings, and to place those rights above human needs, is a profoundly dehumanizing act. It separates power from responsibility and regulation from justice.

Following this path leads to the idea that natural spaces themselves must possess rights—an idea that has generated a chain of ecological, economic, labor, administrative, and demographic problems that shape our present. Only willful blindness could deny this.

Let us not look away. The socio-economic decline of medium- and high-mountain regions—especially within protected areas—and their resulting depopulation have a clear main cause: the Natural Environment Administration, whatever name we choose to give it. Other public bodies have played little or no role; in most cases, their involvement has been marginal at best.

For decades, this administration has acted as the absolute “Lord of the Land,” regulating every possible use, activity, and initiative that local residents might attempt. As a result, marginalized and impoverished inhabitants have been forced to abandon their land and their homes.

Congratulations: the “land managers” can now do as they please. The people are no longer in the way. Those who remain have surrendered.
Below are several examples of population decline in municipalities located within Protected Natural Areas in mainland Spain between 1986 and 2022.
These are not just place names. They are real towns that survived for centuries thanks to the efforts of their inhabitants. Today, their descendants are being steadily pushed out. The population figures show percentage changes compared to the population at the beginning of the period. All data come from Spain’s National Statistics Institute (INE).

Let us begin with the Sierra de la Culebra Protected Landscape and Special Conservation Area, where 61,000 hectares were declared protected.

While Spain’s total population grew by 37% between 1986 and 2022, the population of the Sierra de la Culebra fell by 48%. This 85-point gap can rightly be called a demographic hemorrhage.

Next, consider the Montaña de Riaño and Mampodre Regional Park (León), where 101,000 hectares were protected.

The results are equally bleak. Acebedo, Burón, Crémenes, and Maraña have been virtually wiped out. The park has lost half of its population. If this designation had created real economic opportunities, such an exodus would not have occurred.

Finally, let us look at the Baixa Limia–Serra do Xurés Natural Park in Ourense (Galicia), where up to 30,000 hectares were protected, mostly on privately owned land.

Here, population loss reaches 67%. 
 

The figures speak for themselves.

• From 1986 to 2022, the Montes Obarenses–San Zadornil Natural Park (Burgos) experienced a population decline of 41% across its 16 municipalities. 
• The Sierra de Gredos Regional Park (Ávila) lost 51% of its population in 28 villages during the same period. 
• In the Montaña Palentina Natural Park, population fell by 46% in 10 villages.
• The Arribes del Duero Natural Park saw a decline of 52% in its 24 villages in Salamanca and 46% in its 13 villages in Zamora. 
• In the Serranía de Cuenca Natural Park, 43% of the population left its 12 municipalities. 
• The Sierra de Alcudia and Sierra Madrona Natural Park (Ciudad Real) lost 44% of its population across eight major municipalities. 
• Finally, in the Alto Tajo Natural Park (Guadalajara), 35 municipalities experienced a population decline of 51%.

What has happened in these mountain regions bears the unmistakable imprint of environmental administrations, supported by an endless web of national, regional, and European laws, decrees, and regulations. Together, they have turned these agencies into unquestionable rulers of rural land.

This suffocating regulatory framework has been meticulously designed. It imposes countless prohibitions, restrictions, and obligations on both land and activities. Authorities then enforce every rule with rigor, leaving no room for local initiative or economic development.

Any positive counterexample is merely an exception that confirms the rule.

These long-term demographic trends make one thing clear: the creation of Protected Natural Areas has not delivered the promised social and economic benefits. Yet this promise continues to be repeated by new advocates of new protected areas.

When these spaces were declared, residents were promised prosperity and opportunity. We have shown that these promises were false. For half of the population, protection has meant decline, not progress.

This is what happens when rights are systematically granted to things instead of to people.

ISABEL RUBIO ARROYO | Tungsteno

The world's most extreme roads are routes where engineering and risk go hand in hand. The Yungas Road in Bolivia, with its narrow stretches skirting sheer drop-offs, is among the best known for its extreme danger. China’s Tianmen Mountain Road climbs a mountainside via 99 hairpin bends carved directly into the rock. In the Indian Himalayas, high-altitude passes such as Khardung La, at over 5,300 metres, force drivers to contend with ice, fog, and landslides. In Canada, ice roads exist only in winter, crossing frozen lakes and endless tundra. In this article, we investigate which roads truly deserve the title of the world's most extreme.

“The Road of Death”

The North Yungas Road, known as the Road of Death, links La Paz in Bolivia with the subtropical Yungas valleys and the Amazon region. At just 64 km long and with a descent of 3,500 metres, the road has gained global notoriety due to its extreme danger. The highway is narrow, with sections barely three metres wide, and features tight bends, blind turns, and almost no guardrails. Drivers must contend with sheer drop-offs ranging from 400 to 1,000 metres, as well as dense fog, mud, and waterfalls that render the surface treacherously slippery. Some media outlets estimate that this road used to claim between 200 and 300 lives per year. Despite the risks, the road attracts some 25,000 visitors each year, including cyclists and motorcyclists, who willingly brave the potholes, traffic, and constant threat posed by the surrounding cliffs.

The North Yungas Road challenges drivers and cyclists with its narrow stretches. Credit: World Travel Guide

An “Avenue to the Heavens”

Tianmen Shan Big Gate Road, also known as the Avenue to the Heavens or the Road of 99 Curves, is located in Tianmen Mountain National Park in Hunan, China. This 11-kilometre route climbs from the foot of the mountain to Cave Square, reaching an altitude of around 1,100 metres. Due to its extremely tight hairpin turns, narrow sections running alongside precipices, and frequent fog, it is considered one of the most dangerous roads in the world. Given its proximity to the abyss and minimal margin for error, the route is only suitable for experienced drivers.

In recent years, however, it has also become a popular tourist destination and venue for cycling competitions and mountain races. Its dramatic landscape inspired James Cameron when designing the floating mountains in the Avatar films.

Tianmen Shan Big Gate in Zhangjiajie, China, is known as the Avenue to the Heavens. Credit: Travel and Home

One of the world’s most dangerous mountain passes

Khardung La, located in the Ladakh region of India, is one of the world’s most famous and challenging mountain passes. Rising to 5,359 metres (17,582 feet) above sea level, its extreme altitude exposes travellers to Acute Mountain Sickness (AMS). The road itself is narrow and slippery in places, with several sections in poor condition. Heavy traffic and military convoys can cause delays and increase the risk of accidents on the single lane sections. The pass is also subject to bad weather and geological hazards, such as avalanches, rockfalls, and heavy snowfall, and remains closed for several months each year. The remoteness of the area and poor logistics make the journey even more challenging.

There is no medical assistance available along the entire route, and facilities at the summit are extremely limited. In addition, its proximity to the borders with Pakistan and China results in a heavy military presence, and some travellers require a special permit to cross the pass.

There is usually a military presence at Khardung La. Credit: Vyacheslav Argenberg / Creative Commons.

A road built on ice

The Tibbitt to Contwoyto Winter Road, located in Canada’s Northwest Territories and Nunavut, is the longest heavy-haul ice road in the world. Spanning between 400 and 600 kilometres, it links Tibbitt Lake, near Yellowknife, with diamond mines such as Ekati, Diavik, and Gahcho Kué. It is a seasonal route, rebuilt every year starting in December, and is typically open from February to late March. Around 85% of the road runs over frozen lakes, while the remaining 15% crosses short stretches of permafrost peatland.

Despite being one of the best-managed and safest roads in North America due to strict monitoring and controls, it is still considered dangerous for several reasons. The ice must reach a minimum thickness of 74 centimetres for the road to open and 100 centimetres to support fully loaded trucks. Speed limits for loaded vehicles are restricted to 25 kilometres per hour. Drivers may encounter snowstorms, strong winds and near-zero visibility, and the journey itself can take between 14 and 18 hours in complete isolation. One of the greatest threats to this ice road is climate change, which can shorten the operating season or weaken the ice.

The Tibbitt to Contwoyto Winter Road depends entirely on the thickness of the ice. Credit: Steven TenHave

Tungsteno es un laboratorio periodístico que explora la esencia de la innovación.

Mining and underground works involve the presence of crystalline silica, a naturally occurring mineral known to be carcinogenic. To address this risk, we have implemented a continuous, real-time monitoring system designed to protect the professionals working on our projects.

Royal Decree 1154/2020 classified Respirable Crystalline Silica (RCS) as a carcinogenic agent, significantly reinforcing employers’ obligations in the field of occupational health and safety. In addition, the General Regulations on Basic Mining Safety Standards require an accredited Administration Collaborating Entity (ECA) to take dust samples every four months at workstations where there is a risk of exposure.

Our Health and Safety Department has gone beyond regulatory requirements by deploying a mobile system for continuous, real-time silica monitoring: the AIR S Silica Monitor.

“Having access to real-time data raises awareness of RCS exposure for both workers and management,” explains David Barreda, Prevention Manager at Sacyr Engineering and Infrastructure in Northern Spain.

Crystalline silica is a very common mineral found in rocks, sand, and soil. It is present in construction materials such as concrete and brick, as well as in activities like mining, quarrying, and construction. When its fine dust particles are inhaled, respirable crystalline silica becomes a serious health hazard, increasing the risk of lung cancer, silicosis, and chronic obstructive pulmonary disease (COPD).

​ 
 

The AIR S Silica Monitor was used during excavation works in the tunnels of the Access to the Outer Port of Langosteira project and will later be deployed during ballast spreading for track installation.

RCS levels can vary significantly depending on the stage of construction, with different exposure levels during blasting, debris removal, and drilling operations.

“This new system allows us to make informed decisions and continue reducing our employees’ exposure to RCS,” says David Barreda.

“The company is committed to protecting both our employees and our subcontractors. They value our concern for their health and the continuous control we maintain over the working environment,” he adds.

How the Monitor Works

The system analyzes multiple parameters in real time to detect RCS, including particle size, symmetry, and a range of unique optical markers characteristic of respirable crystalline silica particles.

At the same time, it uses optical refraction technology combined with light-scattering photometry, analyzing each sampled particle and classifying it according to its identifiable optical properties.

This approach allows the system to detect all forms of RCS — including alpha and beta quartz, cristobalite, and tridymite — across all relevant particle sizes within the respirable fraction.

The resulting data is combined with particle mass analysis to provide measurements in both mg/m³ and particles per liter.
Thanks to this comprehensive information, site management can make timely, well-informed decisions to ensure the safety of everyone working on the project.