Luis Esteban
Director Arquitectura en Sacyr Ingeniería e Infraestructuras

Se cumplen 15 años de la rehabilitación del Palacio Velázquez del Parque del Retiro (Madrid) por parte de Sacyr, en la que tuve la suerte de formar parte del equipo como jefe de obra. 

Los trabajos incluyeron la ejecución de una nueva cubierta y la restauración integral del espacio interior. Un trabajo desafiante ya que el edificio cuenta con Nivel 1 de protección con grado singular y está catalogado, dado su valor histórico y artístico.

Fue la primera obra de Sacyr en el emblemático pulmón verde de la ciudad de Madrid y un orgullo para la compañía participar en la restauración del Patrimonio Nacional. 

Imagen del interior recogida de la cuenta oficial del Palacio de Velázquez.

El Palacio de Velázquez fue inaugurado en 1883 como pabellón temporal para la Exposición Nacional de Minería, Artes Metalúrgicas, Cerámica, Cristalería y Aguas Minerales, que se celebró en Madrid ese año, durante el reinado de Alfonso XII.  

Su arquitecto Ricardo Velázquez Bosco le dió nombre al edificio y siguió para su proyecto el modelo que Joseph Paxton había establecido al proyectar el Crystal Palace de Londres. El diseño organiza una arquitectura amplia, cubierta con bóvedas de estructura de hierro, donde el cristal se usa para dotar de iluminación natural a los grandes espacios interiores.

Acabada la exposición el edificio, lejos de demolerse, paso a destinarse a Museo de Ultramar.  Hasta la actualidad donde pertenece al Ministerio de Cultura, quien lo dedica a sala de exposiciones temporales del Museo Nacional Centro de Arte Reina Sofía.

Pese a la antigüedad del edificio, tiene un curioso y actual nexo de unión con la arquitectura contemporánea. Las columnas de fundición, que pueden ser una de las más singulares características del edificio, podrían considerarse como los primeros ejemplos de construcción industrializada porque se fabricaron en taller.  Siendo por tanto una de las primeras semillas de la prefabricación e industrialización, que después de tantos años, se retoma en la actualidad con mucha fuerza.  

  


En este contexto de la construcción del Palacio Velázquez, es relevante indicar que la producción y exportación de hierro había crecido enormemente en España a partir de 1875, y con ello surgieron en Madrid las primeras fábricas de hierro (fundido y colado), desde las cuales se suministró al proyecto.

Todo ello permitió que las columnas de hierro pudieran ser elegidas por catálogo y llegaran a la obra completamente terminadas, solo esperando a ser colocadas. 

El éxito de este edificio le supuso al arquitecto Velázquez el encargo de otros edificios importantes como la Escuela de Ingenieros de Minas y el Palacio de Cristal del parque del Retiro, donde continuó usando soluciones de estructuras metálicas de hierro fundido con el empleo añadido de grandes lucernarios.

The key to this partnership between Sacyr Agua and Dutch company RedStack lies in removing salt from brackish water while generating energy in the process. The two companies will collaborate on various electrodialysis solutions to make this possible.

Electrodialysis reversal (EDR) enables the desalination of brackish water from diverse sources. Its counterpart, reverse electrodialysis (RED), generates energy by exploiting the salinity gradient between brine and freshwater.

Sacyr brings significant experience with EDR technology, having built the world’s largest EDR facility: the Abrera plant in Barcelona, with a capacity of 200,000 m³/day. We also operate other plants, such as Valle Guerra (San Cristóbal de La Laguna, Tenerife), where we desalinate treated wastewater using a membrane bioreactor (MBR) to produce high-quality water for irrigation.

Reverse electrodialysis (RED) generates energy by utilizing the salinity difference between two water streams—typically brine and freshwater. We are especially interested in applying RED to recover energy from the combination of brine from desalination plants and effluent from municipal wastewater treatment facilities.

Sustainable use of brine

Sacyr and RedStack have successfully tested RED technology at a pilot project through the LIFE HyReward project, funded by the European Union. The project has achieved energy recovery rates of up to 0.3 kWh/m³.

In LIFE HyReward, we explored the potential of generating renewable electricity from the brine produced during desalination. The goal was to enhance the energy efficiency of the process by combining reverse osmosis with reverse electrodialysis. Integrating this approach with conventional technologies makes desalination more sustainable by recovering electrical energy from brine before it is discharged into the sea, thereby reducing CO₂ emissions.

As part of their long-term collaboration, Sacyr will deploy REDstack’s EDR and RED systems in projects focused on salt removal and energy generation from brine streams. Additionally, the two partners are currently evaluating the site for a pilot plant that will use RedStack’s next-generation EDR technology, which offers advantages such as greater productivity and lower energy consumption compared to other solutions on the market.
 

ISABEL RUBIO ARROYO | Tungsteno

From the Hand of the Desert in Atacama, Chile to the Hands of Harmony in South Korea, or the hands of the Golden Bridge in Vietnam—all these sculptures feature the same body part, but each has its own story. Why have so many artists found inspiration in the human hand? We investigate the mysteries behind the largest hands on the planet.

A hand in the middle of the desert

In the heart of the Atacama Desert in Chile, a giant hand 11 metres high juts out of the arid sand, its fingers pointing skywards. The reinforced concrete sculpture was created in 1992 by the Chilean artist and sculptor Mario Irarrázabal. Located about 75 kilometres north-west of the city of Antofagasta, it has become one of the main tourist attractions in the area. But it is not the only hand that Irarrazábal has created. There are also other versions on the Playa Brava beach in Punta del Este, Uruguay, and in the Juan Carlos I Park in Madrid.

The sculptor was commissioned by the cement company Melón Hormigones to make Hand of the Desert for the entrance to their plant in Los Andes." Irarrazábal recounts: "It would have looked terrible. Luckily, Melón was going through a huge financial crisis at the time and they told me to forget about it." He showed the project to an engineer from Antofagasta, who asked him to let him talk to his friends, who were "mining engineers and very technical people." These people, above all, "loved the desert." "Let's do it," they replied.

Hand of the Desert is one of Chile's most iconic sculptures Credit: PxHere

The engineers didn't even ask about the meaning of the hand. Each visitor can give it their own interpretation, says its creator. While some believe it is the city saying farewell to the traveller, others claim it represents the victims of injustice and torture during Chile’s military dictatorship from 1973 to 1990. Today, many people come here to observe the starry sky. "Here, you can see the plane of the Milky Way, the Southern Cross and the Magellanic Clouds, as well as a large number of bright stars, such as Antares, Altair and Alpha Centauri, among many others," says astronomer Maximiliano Moyano D'Angelo.

Hands supporting bridges or emerging from water

In the hills of Vietnam, other giant concrete hands cradle a 152-metre-long pedestrian bridge suspended almost 1,400 metres above sea level. The bridge is known as Cau Vang (Golden Bridge) and was designed to make visitors feel like they are taking a stroll on a shimmering thread stretched across the hands of God.

This megastructure is part of a 1.7 billion euro project to attract tourism to the Thien Thai gardens at the Bà Nà Hills Resort. And it worked. Thousands of tourists have flocked to the area and pictures of it have gone viral on social media. "We’re proud that our product has been shared by people all over the world," TA Landscape Architecture's principal designer and founder Vu Viet Anh told AFP.

The Golden Bridge has gone viral on social media. Credit: Amazing Things in Vietnam

A pair of similar looking hands can be found in Homigot, South Korea. These imposing steel hands face each other (about 100 metres apart) and represent coexistence and harmony. They are known as the Hands of Harmony. One of them rises from the sea and offers a unique view at sunrise, while the other is on land at the Homigot Sunrise Plaza. Located at the easternmost tip of South Korea, Homigot is the first place in the country to see the rising sun. In fact, a sunrise festival is held here every New Year’s.

These are just some of the most striking giant hands on the planet, but there are many more. Italian artist Lorenzo Quinn designed six pairs of monumental stone hands for the 2019 Venice Art Biennale, which come together to symbolise "six of humanity’s universal values: friendship, faith, help, love, hope and wisdom." Other sculptures include the Praying Hands in Tulsa, Oklahoma; the Holocaust Memorial in Miami Beach, Florida; and the Caring Hand in Glarus, Switzerland. Their ability to convey universal meaning and their powerful visual impact have made these giant hands a magnet for millions of tourists around the world.

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ISABEL RUBIO ARROYO | Tungsteno

From a young age, Danish architect Bjarke Ingels dreamed of becoming a cartoonist. Hoping to improve his drawing skills, he enrolled at the Royal School of Architecture in 1993.

“Drawing is my superpower. It was during my childhood: in kindergarten, in high school. I was always the best at drawing,” he said in an interview with the Spanish newspaper El País. At that time, he had no idea that he would become one of the most famous architects on the planet.

From aspiring cartoonist to influential figure

In 2016, when he was 42 years old, Time magazine named him as one of the 100 most influential people in the world. “I do not consider Bjarke Ingels the reincarnation of this or that architect from the past. On the contrary, he is the embodiment of a fully fledged new typology, which responds perfectly to the current zeitgeist," said renowned architect Rem Koolhaas, who worked with Ingels for a time. Koolhaas sees the Danish architect as “completely in tune with the thinkers of Silicon Valley, who want to make the world a better place without the existential hand-wringing that previous generations felt was crucial to earn utopianist credibility.”

Ingels, 49, founded the architecture firm Bjarke Ingels Group, better known by its acronym BIG, in 2006. The firm is behind landmark projects such as the VIA 57 West skyscraper in Manhattan, Google's North Bayshore headquarters in California, and the 8 House housing complex, Superkilen Park and the Amager Resource Center waste-to-energy plant in Copenhagen. BIG also designed LEGO House, a giant structure that appears to be built of LEGO bricks, which began construction in 2014. What all these structures have in common is innovative design.

Ingels is an architect recognised worldwide for his innovative and avant-garde approach. Credit: Architects not Architecture

A giant LEGO house

Ingels is a LEGO enthusiast. Before he and his team set to work on the project to build a giant LEGO house, they spent time playing and building with these iconic bricks. “They soon discovered that the systematic creativity of LEGO play often matched the way they approached an architectural task,” the LEGO Group explains.

The giant structure designed by Ingels, known as LEGO House, is an educational and activity centre in Billund, Denmark. The architect's idea was to create “a cloud of interlocking LEGO bricks… a literal manifestation of the infinite possibilities of the LEGO brick.” The aim was to stack 21 white bricks, one on top of the other, and crown them with a keystone inspired by the classic eight-knob LEGO brick. Underneath, there is a covered public square and interconnected terraces.

LEGO House has a total floor area of almost 12,000 square metres, of which 8,500 m² are above ground and 3,400 m² are below ground. The 23-metre-high building is clad in white bricks measuring 18 by 60 centimetres to give the impression that the structure is composed of LEGO bricks. The terraces are brightly coloured and their surfaces are made from materials left over from the production of trainers for several international sports brands, says the company.

LEGO House opened its doors for the first time in 2017. Credit: WIRED UK

Today, Ingels is considered a visionary and creative artist who has transformed the landscape of architecture. He describes himself as someone “capable of changing things.” He is convinced that “architecture can be an art, but actual art must be transformative.” “Steve Jobs said that for every 20 engineers, one is an artist and the rest are engineers. I think that can be applied to architecture, handball and teaching. A teacher who is an artist can change people,” he concludes.

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ISABEL RUBIO ARROYO | Tungsteno

The Silk Pavilion I is an architectural structure created with a base woven by a robotic arm and the help of thousands of live silkworms. "We ordered 6,500 silkworms from an online silk farm. After four weeks of feeding, they were ready to spin with us," says Neri Oxman, the leader of the initiative. We investigate the most innovative projects of this 48-year-old Israeli-American architect, known for fusing architecture, design, biology and materials engineering.

From Henry Ford to Charles Darwin

Assembly lines have dictated a world made of parts, "framing the imagination of designers and architects who have been trained to think about their objects as assemblies," says Oxman. In contrast, the architect argues that assemblages of homogeneous material are not found in nature. She cites human skin as an example. "Our facial skins are thin with large pores. Our back skins are thicker, with small pores. One acts mainly as a filter, the other mainly as a barrier, and yet it is the same skin: no parts, no assemblies," she said in a TED talk.

Architects and designers face a dichotomy: that of working between the machine and the organism. Or as Oxman puts it, "between the chisel and the gene, between machine and organism, between assembly and growth, between Henry Ford and Charles Darwin." "My work, at its simplest level, is about uniting these two worldviews, moving away from assembly and closer into growth," she explains.

Oxman explores how digital fabrication technologies can interact with the biological world. Credit: TED

More than 6,000 silkworms weave the architecture of the future

It is in this fusion that one can understand her Silk Pavilion I, in which biological silk and robotically spun silk intermingle. To construct it, she and her collaborators carefully placed 6,500 worms on the bottom edge of a silk frame spun by a robotic arm. The silkworms spun their silk, mated and laid eggs. In little more than two to three weeks, "6,500 silkworms weave 6,500 kilometres."

In this work, her two visions of the world are integrated: "One spins silk out of a robotic arm, the other fills in the gaps." "If the final frontier of design is to breathe life into the products and the buildings around us, to form a two-material ecology, then designers must unite these two worldviews," she says.

Later, the architect and her team developed the Silk Pavilion II. Commissioned for the Material Ecology exhibition at the Museum of Modern Art in New York, the structure is six metres high and five metres wide. "Ten days of co-creation among silkworms, humans and a robotic loom-like jig resulted in a structure made of silk threads longer than the diameter of planet Earth," explain its creators.

More than 6,000 worms were involved in the construction of the Silk Pavilion. Credit: Oxman

Fallen leaves, apple skins and shrimp shells

Oxman has become a prominent figure in the field of material ecology. This discipline integrates technological advances in computational design, synthetic biology and digital fabrication to create revolutionary design solutions inspired by nature. Her team in the Mediated Matter group at the MIT Media Lab experiments with everything from moss to mushrooms to apples.

One of her most striking projects is Aguahoja I, which aimed to develop a robotic platform for 3D printing biomaterials. The result is a pavilion made of 5,740 fallen leaves, 6,500 apple skins and 3,135 shrimp shells. Also noteworthy is her synthetic apiary, which aims to combat the decline of bee populations. This initiative proposes the creation of controlled, indoor environments that simulate ideal conditions for bees to thrive throughout the year.

Oxman's work has been seen on fashion catwalks and at design fairs. They have also been exhibited in prestigious museums around the world, including the Museum of Modern Art and the San Francisco Museum of Modern Art. In addition to winning several awards (including the Cooper Hewitt Design Award and the Vilcek Prize in Design), her creations led Jenny Lam, a leading technology designer, to describe Oxman as a contemporary Leonardo da Vinci.

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ISABEL RUBIO ARROYO | Tungsteno

Did you know that the Casa Rosada is not symmetrical due to the demolition of one of its parts? Why does it have a room full of false doors? What is the reason for its pink colour? We investigate the secrets of Argentina's seat of government, which was almost fitted with a great dome and hides priceless archaeological remains inside.

An asymmetrical masterpiece

The Casa Rosada is located in the historic centre of the Autonomous City of Buenos Aires. Its history begins in 1873, when the Palacio de Correos y Telégrafos (Palace of Posts and Telegraphs) was erected. A few years later, President Julio Argentino Roca dreamed of a definitive government palace. He designed it next to the Palacio de Correos. In 1886, the two buildings were joined by the majestic portico that now greets the Plaza de Mayo. Thus was born the Casa Rosada. More than half a century later, in 1938, the south wing was demolished, as a result of which the Casa Rosada is no longer symmetrical.

A hall full of false doors

The White Hall is where the most important acts of government take place. It is where official ceremonies are held, foreign dignitaries are received and important decisions for Argentina are made, such as the signing of international treaties. The balcony or high gallery that surrounds it hides a secret: it is adorned with false doors covered with mirrors. The aim is to create a sense of greater breadth and depth, enhancing the grandeur of the space. “Only one of the doors opens, the one located in the centre of the right-hand sector leading into the hall,” says the official website of the Casa Rosada.

The White Hall is the main hall of the Casa Rosada. Credit: Casa Rosada official website.

The mystery of its colour

The choice of pink for this emblematic building is often attributed to President Domingo Faustino Sarmiento. It is said that Sarmiento, who assumed the presidency in 1868, used the mixture of white and red to symbolise the union of all the political sectors of the time. “According to some versions, the original method used to obtain the characteristic pink colour of the Casa de Gobierno was to mix lime with cow’s blood, a common technique at the time due to the water-repellent (to avoid moisture and filtrations) and fixing properties of the blood,” says the official website.

The dome that never was

The Casa Rosada was on the verge of having a majestic dome on its west façade. In 1907, the General Directorate of Architecture presented a project to transform the building's appearance. The idea was to construct a great dome that would symbolise grandeur and modernity. In the end, however, the project was never carried out. The reasons why it was left on the back burner of history are not documented.

The Casa Rosada was on the verge of having a majestic dome. Credit: Casa Rosada official website

The buried past of the Casa Rosada

At the beginning of the 20th century, excavations were carried out in the Patio de las Palmeras of the Casa Rosada and an unexpected discovery was made: rounded stones that, according to the renowned archaeologist Juan Bautista Ambrosetti, could be instruments used by the indigenous people of the area. Specifically, he suggested that they could be stones from boleadoras (a throwing weapon used mainly for hunting) or hatchets used by the Querandí people, indigenous South Americans who inhabited the Pampean region of present-day Argentina.

These are not the only mysteries hidden in the Casa Rosada. In fact, other surprising discoveries have been made under its floors. Most recently, in 2018, during the excavation of a pit for the installation of new lifts, ruins were found three metres underground. They belong to the Palace of the Viceroys of the Río de la Plata and date back to the 18th century. All these curiosities make the Casa Rosada more than just a government building. It is a unique place that attracts millions of tourists every year for its historical, cultural and architectural value.

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The new Sótero del Río Hospital (Santiago de Chile, Chile) is bound to be one of the largest healthcare facilities in Latin America, and also one of the most sustainable. This project, developed by Sacyr Engineering and Infrastructure, has obtained the Zero Waste certificate, and is now conducting a novel pilot to introduce a hybrid boom truck fueled by green hydrogen into its fleet. 

The aim is to improve the efficiency and reduce emissions produced by diesel trucks by implementing a hybrid green hydrogen injection system into the combustion chamber.

The new dual combustion system has been designed in Italy specifically for this vehicle model, as it is the first time it has been implemented in a boom truck. The installation of this kit was carried out by AndesH2, a company that has experience in Colombia and Chile. 

"This innovative project arose from the urgent need to reduce the emissions generated by the equipment used on site. Considering that, in the long term, we must focus on progressively forming and shifting a fleet of heavy equipment with zero emissions, including hopper trucks, backhoes, trucks with lifting equipment, among others," explains Rodrigo Fernández, Construction Manager at Sacyr's Metro L7 in Chile.

"Our main purpose is to evaluate the technical and economic feasibility of the gradual conversion of Sacyr's current fleet to low-emission equipment, thus ensuring compliance with more rigorous environmental standards and actively contributing to the sustainability of the sector," Rodrigo says.
"Our goal is to evaluate the benefits of introducing synthetic fuels such as green hydrogen," explains Etienne Valdés, R+D with Sacyr Chile's Innovation Department.

The project consists of the implementation of a dual combustion system designed in Italy specifically for the truck model. The installation of this kit was carried out by AndesH2, a company that has experience in Colombia and Chile implementing these modifications and being the first time that it has been carried out on a boom truck.

This process is called dualization or blending of green hydrogen to improve fuel efficiency. The installed kit is connected to the hydrogen tanks and injects the appropriate hydrogen percentages into the engine.
 

Preliminary first tests have already been carried out using 4 kg of hydrogen for a week in a controlled setting closed to traffic.

"It takes less hydrogen than diesel to reach the same energy efficiency in the engine. The engine is modified to inject 15% hydrogen on average into the fuel. This improves efficiency and reduces the use of diesel, so the engine is more efficient, and produces fewer emissions," explains Etienne.

The use of this fuel poses further challenges. "We have to create a safety plan with this equipment, and, as a second step, homologate the truck for use on public roads. Currently, we are managing an experimental permit certificate through the Ministry of Transport and Telecommunications, explains the expert.

Tenemos nuevo capítulo de Sacyr iPodcast en el que hablamos de innovación con expertos que nos inspiran y nos ayudan a ampliar nuestra visión.

En este nuevo episodio, Marta Gil continúa la conversación sobre industrialización en los procesos constructivos con Ramón Sanchez y Antonio Jiménez-Peña.

Si te perdiste el anterior, puedes verlo aquí

En el capítulo nuevo, analizamos las ventajas de esta técnica constructiva, a través de ejemplos concretos de proyectos industrializados de Sacyr.

Aquí puedes verlo completo:

In this installment of the Circular Transformation series, Paula Honrado and Gonzalo Vicente, from the Environment, Quality and Energy Department, explain the concept of the circular economy as a model to keep natural resources within the production cycle.

Prioritizing materials with recycled content, working with local suppliers, and properly managing the waste we generate are key factors in reducing emissions.

In 2024, over 92% of the waste generated from Sacyr’s activities has been reused, recycled, or recovered. Since 2020, we have avoided emitting nearly 10,000 tons of CO2 and have recovered more than 23 million units of waste.

Gabriel Palacios Hernández
Prevention officer and Head of Drone Operations

Sacyr always strives to undertake our projects with prevention and safety as primary objectives. In pursuit of this improvement, we decided to become drone operators in February 2017, as we believed that the use of Remotely Piloted Aircraft Systems (RPAS) (more commonly known as drones) would yield significant benefits, providing greater agility and safety in fieldwork.

In addition to reducing risks in our sector, they also aid production, becoming smaller, more manageable, resistant to weather conditions, and equipped with features that make their flights more efficient and faster.

Drones have countless applications, with new ones emerging daily, but the challenge lies in discovering these uses because the technology is already here, waiting to be applied.

Infrastructure inspection

In infrastructure inspection, RPAS can perform reviews without requiring a worker to be suspended by a lifeline on a slope or in a basket beneath the deck of a bridge. The risks are substantially lower because the worker is not exposed, and work efficiency is much higher because the task is completed in less time.

The use of RPAS is now widespread in surveying, using photogrammetry to obtain 3D models of terrain and orthophotos, which are high-resolution photographs obtained from the combination of partial photos in which distances, areas, and volumes can be measured with great precision.

Replacing operators with RPAS in confined spaces, inspecting high-voltage towers or wind turbines, and using underwater RPAS for inspecting treatment plants or collectors are tasks already being performed, significantly reducing risks.

It is important to consider that drones have their own usage risks, which, thanks to aviation regulations and their high safety standards, are closely monitored to prevent, primarily, the uncontrolled fall of these devices on people or material goods.

Like any flying device, it is susceptible to ceasing flight in an unplanned manner, becoming a weight that, aided by the speed it acquires in the fall, can be fatal. The smallest professional drones weigh around one kilogram, so we can imagine what they can become in free fall.

Additionally, RPAS are devices with propellers, batteries that could ignite, and are powered by electricity in most cases. All of this can lead to accidents for the people who operate them.

Photogrammetry

In what activities can we use drones within our sector?

- Photogrammetry work for topographic surveying: Photogrammetry has transformed the way surveyors work. Instead of traversing the terrain to be "surveyed," obtaining the different points, now the drone performs that work for them. The arrival of drones with integrated RTK systems has further reduced the need for obtaining control points.
- Building inspection or construction monitoring: The activity of "construction monitoring" through aerial images and videos is increasingly in demand. It is the best viewpoint to see the progress of the work.
- Inspection of structures in civil works: If we use the drone to approach the structure to be inspected, being able to capture images or videos, we avoid placing the worker in those areas and the use of costly auxiliary means.
- High-altitude inspection of high-voltage towers: Traditionally, this activity has been carried out by the worker ascending the tower itself, from an aerial lift, or from a helicopter, which is positioned at the top.  Drones clearly avoid putting the worker at risk of falling from height and at risk of electrocution, among others, incorporating RGB cameras with powerful zooms or with thermographic cameras.
- Confined space inspection: There are already drones of minuscule dimensions that do not suffer damage during their impact in narrow areas, with high-quality television cameras, that can replace operators in these tasks.
 

ISABEL RUBIO ARROYO | Tungsteno

St. Peter's Basilica is not only the spiritual heart of Catholicism, but also a monument that encompasses centuries of art, architecture and mystery. From its origins in the time of Constantine to its underground nooks and passageways, this monumental temple continues to fascinate millions of faithful and visitors every year. Here are some of the most surprising and lesser-known facts about the world’s largest Christian church.

The history behind St. Peter's Basilica

The St. Peter's Basilica that we know today was not the first church to occupy this site. In the 4th century, Emperor Constantine commissioned a church to be built here, which stood for over a thousand years. However, it was not until 1506 that Pope Julius II decided to replace it with a new, monumental construction in tribute to the Apostle Peter, who is believed to have been buried on that very hill in the Vatican. Construction took almost 120 years and involved the participation of prominent Italian architects and artists such as Donato Bramante, Michelangelo and Raphael. While Bramante took inspiration from the Roman Pantheon for his initial design, Michelangelo was responsible for the iconic dome.

The imposing interior of St. Peter's Basilica. Credit: Fabbrica di San Pietro / St. Peter's Basilica

The largest Christian church in the world

This monumental work embodies the splendour of the Vatican. At 136.5 metres high, its dome is the tallest in the world. The interior covers more than 15,000 square metres and its total area extends to about 2.3 hectares. Recognised as a UNESCO World Heritage Site in 1984, it is considered the largest Christian church in the world.

View of the interior of the dome of St. Peter's Basilica. Credit: Fabbrica di San Pietro / St. Peter's Basilica

Saints welcome the faithful in the iconic St. Peter's Square

In front of the basilica, St. Peter's Square can host thousands of people. According to the Vatican's official website, Vatican News, more than 100,000 people attended Pope Leo XIV’s first greeting from the square. Designed by Gian Lorenzo Bernini, the square features an elliptical colonnade arranged in 284 columns in four rows, which symbolise the embrace of the Church. At its centre stands an Egyptian obelisk, flanked by two fountains. The square is adorned with statues of saints who welcome visitors and, according to the Vatican, represent the union between the heavenly and earthly churches.

St. Peter's Square and its iconic colonnade. Credit: Fabbrica di San Pietro / St. Peter's Basilica

The popes who rest beneath St. Peter's Basilica

Throughout history, St. Peter's Basilica has inspired numerous legends about hidden passageways and secret chambers beneath its structure. Beyond the myth, the truth is that there are several real underground spaces, such as the Vatican Grottoes and the Necropolis, which house ancient papal tombs. Although Pope Francis has chosen the Basilica of Saint Mary Major as his burial place, the remains of 91 popes lie beneath Saint Peter's. These papal tombs are located alongside those of members of royalty and nobility. Notable pontiffs buried here include emblematic figures such as Pius X and John Paul II. For archaeologists, this collection of tombs is a historical treasure of incalculable value.

The Vatican Necropolis. Credit: Fabbrica di San Pietro / St. Peter's Basilica

The Vatican's secret passageway

Very close to this monumental complex is the Corridor of Borgo, also known as the Passetto de Borgo, a fortified corridor connecting Vatican City with Castel Sant'Angelo. Although it doesn’t pass directly under the basilica, it forms part of the Vatican's defensive system and was constructed as an escape route for popes during times of crisis. The corridor’s most famous episode occurred during the Sack of Rome in 1527, when Pope Clement VII managed to escape through it and took refuge in the castle. According to Rome's Department of Major Events, Sports, Tourism and Fashion, “the Pope was saved by the skin of his teeth, running through the narrow corridor, while the courtiers and nobles who accompanied him protected him with a dark cloak to prevent his white robe from becoming an easy target.” Today, some sections of the Passetto can be visited on guided tours from Castel Sant'Angelo, revealing one of the most strategic and lesser-known corners of Vatican history.

View of the Passetto di Borgo from Castel Sant'Angelo in Rome. Credit: Rome's Department of Major Events, Sports, Tourism and Fashion

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ISABEL RUBIO ARROYO | Tungsteno

Almost 100 kilometres off the coast of Baku, in the middle of the Caspian Sea, rises Neft Daşlari, an industrial city built on platforms. Its name, meaning “Oil Rocks,” reflects its function: a vast network of extraction wells and processing plants linked together by kilometres of steel bridges. Accessible only by a lengthy boat ride from the mainland, this enigmatic city floats in the middle of the world's largest enclosed body of water.

A motorway in the middle of the sea

Founded in 1949, Neft Daşlari began with platforms built atop deliberately sunken ships. Over time, it evolved into a vast industrial city, linked by more than 200 kilometres of trestle bridges and supported by nearly 100 kilometres of pipelines transporting oil and gas. At its peak, the city boasted nearly 2,000 oil wells and some 320 production plants.

But Neft Daşlari is about more than industry—it has homes, shops, a theatre, a heliport and even a soccer field. Trees were even planted atop steel structures, and at its height, the city housed over 5,000 inhabitants. In recent decades, however, the population has dwindled and much of the infrastructure has fallen into disrepair, with some parts claimed by the sea.

Oil Rocks has served as the dramatic setting for numerous documentaries and films, including scenes from the 1999 James Bond film The World Is Not Enough. It has also inspired renowned Azerbaijani artists, such as composer Gara Garayev and artist Tahir Salahov. Filmmaker Marc Wolfensberger, who shot the movie Oil Rocks: City Above the Sea, described the site as “beyond anything I had seen before.” As he told CNN, it was like “a motorway in the middle of the sea” that stretched out “like an octopus.”

Trailer for the documentary Oil Rocks: City Above the Sea. Credit: Marc Wolfensberger

"The Island of Seven Ships," a symbol in Azerbaijan

To shield the structure from the wind and waves of the Caspian Sea, seven decommissioned ships were deliberately sunk, their hulls forming an artificial bay around the original island. “Some of those ships are visible on the surface of the water where they were buried,” Mirvari Gahramanli, head of the Oil-Workers Rights Protection Organisation, told CNN. In Azerbaijan some refer to Neft Daşlari as “the island of seven ships” and even “the eighth wonder of the world,” she added.

Today, the oil field remains operational. Over the decades, 1,983 wells have been drilled, with 432 still active. According to SOCAR, Azerbaijan’s state-run oil company and the operator of Neft Daşlari, the field produced an average of 2,865 tons of oil per day as of 1 January 2024. Since production began, the site has yielded a total of 179.8 million tonnes of crude oil and 14.092 billion cubic metres of natural gas. Peak output was reached in 1967, when it produced 7.6 million tonnes of oil—about 4.5% of the total cumulative volume.

The industrial city is still operational with more than 400 active wells. Credit: SOCAR

The uncertain future of the “floating” city

Neft Daşlari’s importance has declined in recent decades, overshadowed by the development of larger fields and fluctuating oil prices. “The production at Neft Daşlari supplies only a minor part of Azerbaijan's oil production,” explains Brenda Shaffer, an energy expert at the U.S. Naval Postgraduate School, who has advised oil and gas companies in the Caspian region. As output has declined, so too has the population, now estimated at around 2,000. Moreover, the floating city has not been without controversy: beyond the danger faced by those living or working there due to extreme weather conditions, Gahramanli has raised concerns about the discharge of raw sewage and reports of oil spills.

The floating city’s production now accounts for only a small share of Azerbaijan’s oil output. Credit: SOCAR

With its reserves gradually running dry, the future of this sprawling offshore settlement remains uncertain. Shaffer suggests it could one day become a tourist attraction. Filmmaker Marc Wolfensberger envisions a different future: “It’s really the cradle of offshore oil exploration,” he said, imagining it repurposed as a museum. As for the risk of it sinking—either due to structural fatigue or the effect of climate change—Mirvari Gahramanli was firm when asked by the BBC: “The island is not about to sink and, at the moment, no such risk is foreseen.”

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

The terrain that characterizes the surroundings of the Sicilian city of Catania is unique due to the omnipresence of Mount Etna. The eruptions over time have shaped a capricious and highly variable subsoil. 

In this environment, we will develop a major railway project: the Metropolitana di Catania expansion, with a budget of nearly 800 million euros. The extension covers almost 14 km of line, of which eight and a half are underground sections of various kinds. This expansion will connect several towns in the metropolitan area.

Ferrovia Circumetnea (FCE), an agency under the Italian Ministry of Infrastructure and Transport, awarded SIS—a permanent consortium formed by Finninc (51%) and Sacyr (49%)—a section between the towns of Misterbianco and Paternò in September 2023, and in December 2024, a complementary section between Monte Po (Catania) and Misterbianco, connecting with the currently operational line.

This project will feature the use of a new and uncommon tunnel boring machine known as the Variable Density TBM (VD-TBM). Only about 20 machines of this type have been ever operated worldwide. 

The handover ceremony for the TBM took place on May 27, with representatives from Herrenknecht (the TBM manufacturer), SIS (Finninc and Sacyr), and FCE (Ferrovia Circumetnea) in attendance.
 

It stands out for its adaptability to the area’s changing geological conditions. Additionally, due to the frequent seismic activity generated by the volcano, it is necessary to comply with strict seismic standards for both permanent and temporary works.

“A few years ago, the city already undertook a metro project using a conventional TBM, and it ran into significant difficulties due to the unfavorable geological conditions”, explains Miguel Ángel Montón, tunnel manager for this project.

“The ground is extremely complex due to its heterogeneity; there are fissures, cavities, and frequent alternations between basaltic rock—lava—and softer soils. Our TBM is highly adaptable to current conditions; its operating mode can be changed on the fly using four different excavation modes, allowing us to respond in real time to the terrain. It is more complex to operate, but offers that flexibility”, Montón adds.

This isn’t the first time that Montón faces this kind of challenge, as he had a similar experience on Line 3 of the Guadalajara Metro (Mexico). “It was more complicated than usual, but not as challenging as this project,” he states.
 

The TBM began manufacturing in August 2024  and operational testing started in May this year.  Disassembly and transport to the construction site are scheduled to begin in June, with arrival expected in July.

The heaviest components will be transported across the Alps using special convoys to the port of Ravenna (Italy), from where they will be shipped to Catania. The smaller components will be transported by truck to across the Strait of Messina to reach Sicily. 

On-site assembly of the machine will take around three months, followed by approximately two weeks of commissioning and testing. Excavation is expected to begin by the end of December or early 2026.

“We will excavate around 5 km of tunnel with this TBM. The initial contract was for 3,200 meters, and with the most recent award, an additional 2 km were added,” Montón explains.

In a joint initiative between our Innovation team and Sacyr Water and Energy, we’ve launched a renewable energy project at the Pamasa P3 project in Palma de Mallorca. This initiative will support the asset’s decarbonization and help avoid 20 tonnes of CO₂ emissions annually.

Pamasa operates the 45.2 km highway connecting Palma de Mallorca and Manacor (Balearic Islands), a key transport corridor that plays a vital role in regional connectivity.

The new 32 kWp solar installation at Pamasa includes a 41 kWh battery storage system and two EV charging points. A total of 55 photovoltaic modules will generate approximately 47,021 kWh of renewable electricity each year.

Miguel Bauzá, Operations Director at Sacyr Concesiones, said:"This project reinforces our commitment to renewable energy and sustainable mobility".

Once operational, 42% of Pamasa’s electricity needs will be covered by solar panels, rising to nearly 70% with the addition of battery storage.

Of the total energy generated:

• 42% (19,749 kWh) will be used for direct self-consumption
• 27% (12,696 kWh) will be stored for use at night
• The remaining 31% will be fed into the grid

The project will also save an estimated 2,000 liters of fuel each year thanks to the new EV charging stations.
 

Driving decarbonization 

This is one of nearly 100 initiatives in our Decarbonization Plan, which spans Sacyr’s various business units.

These efforts are coordinated through specialized working groups that promote our climate strategy by tracking both emissions reductions and economic savings across each project.
 

Other solar installations

At the Turia Highway Control Center in Valencia, we’ve built a 120 kWp solar array using 570 Wp modules and a 100 kW inverter. This setup produces around 170,000 kWh annually — enough to meet 34% of the center’s energy needs.

In Cádiz, at the Aguas del Valle del Guadiaro facility, we installed a 250 kWp solar system with four 50 kW inverters, producing around 390,000 kWh per year and supplying 20% of the site’s energy consumption.
 

In Santa Cruz de Tenerife, at the Emmasa desalination plant and various water tanks, we’ve deployed multiple solar installations for both individual and shared self-consumption. Combined, they total 900 kWp using 585 Wp modules and a range of inverter sizes.

On Brazil’s RSC-287 highway, we’ve installed five solar power stations that collectively generate nearly 396,000 kWh annually.
 

Progress from 2020 to 2024

Since our baseline year of 2020, we have:

• Reduced Scope 2 emissions by 28,621 tonnes of CO₂ equivalent
• Generated 4,299 MWh of renewable energy
   

This is the third chapter of Sacyr iPodcast, a space where we talk about innovation with experts who inspire us and help broaden our perspective.
In this new episode, we delve into the industrialization of construction processes, a key topic in the transformation of the infrastructure sector.

You can watch it here:

In this conversation, Marta Gil, Chief Strategy, Innovation and Sustainability Officer; Ramón Sánchez, Building Engineering Manager at Sacyr Engineering and Infrastructure; and Antonio Jiménez-Peña, Head of the Installations Department at Sacyr Engineering and Infrastructure, explore the main advantages of industrialization in construction.

Industrialized construction involves off-site fabrication of modular components using replicable elements, allowing for faster construction, improved quality, cost reductions, and enhances both sustainability and productivity.

“It’s a different way of doing things. We produce large structural elements with diverse components, transport them to the site, and connect them with others. The key lies in the controlled environment where safe, serial production takes place. At Sacyr, doing things differently—faster and better—is in our DNA,” says Ramón Sánchez.

“Clients are very receptive to the speed potential of industrialized projects. Plus, buildings no longer all look the same —technology enables unique constructions, making them more attractive,” the expert adds.

“We must lead the way in integrating these processes into the workflows of installers who are still using traditional solutions,” says Antonio Jiménez-Peña.

“From an installations standpoint, there’s a wide range of solutions. Right now, we’re seeing significant progress with utility corridors and riser shafts—we’re working on how to integrate them into modular systems,” he notes.

Industrialized projects 

Sacyr’s major projects involving industrialized elements include the Hospital 12 de Octubre in Madrid, the Hospital Sotero del Río in Chile, the Expo 2008 Civic Initiatives Pavilion in Zaragoza, the Hospital Buin-Paine in Chile, the Milan Hospital in Italy, the Velindre Hospital in Wales, the Boadilla Hospital in Madrid, and various residential buildings in Madrid, among others.

ISABEL RUBIO ARROYO | Tungsteno

Coastal flooding worldwide surged by almost 50% between 1993 and 2015, according to a study by Nature Communications. And the future looks more alarming: by 2050, coastal areas currently home to 300 million people could face annual inundation. As climate change accelerates, mitigating the impact of flooding is crucial for our survival. Here’s how architects and designers are building resilience into structures—one innovative solution at a time.

Architectural innovation against flooding

"While many buildings are decades old, new innovations in architecture and construction practices are showing how buildings can survive major flooding events without leading to a total loss of property," says TrapBag, a company that designs flood control systems. The company sees a need for more flood-proof housing: "Even if a new building is not currently in a flood zone, that may change in 20 or 30 years."

One example of a building designed with flooding in mind is the Spaulding Rehabilitation Hospital on the Boston waterfront. It was designed to be elevated above the projected flood level for rare events that are expected to occur once every 500 years. Additional protective measures include berms as barriers and a perimeter drainage system. These features help to reduce the risk of flooding while supporting the hospital’s ability to remain operational—should water reach the ground floor, equipment and workstations can be quickly relocated to higher levels.

Other notable examples include the Bundanon Art Museum in Australia, which features an underground structure and an elevated bridge that allows water to flow underneath; the St Petersburg Pier in Florida, designed to withstand extreme storms thanks to its elevated infrastructure and efficient drainage systems; and the Merrion Cricket Club in Dublin, which uses waterproof concrete and movable barriers for protection. In the UK, the Michael Baker Shed is raised on a sturdy base to keep key areas above flood levels. Meanwhile, DC Water's headquarters in Washington, D.C., was built above the floodplain, while the Pérez Art Museum Miami uses porous soils, rain gardens and native vegetation to defend against rising waters.

Over millennia, fire and floods have sculpted the landscape surrounding the Bundanon Art Museum. Credit: Architizer

How to flood-proof buildings

Very few buildings are completely flood resistant, but their resilience varies according to location. "A home is typically considered flood-resistant if it can experience at least three days of floodwaters without sustaining significant or non-cosmetic damage," says Trapbag. In flood-prone areas, experts recommend building the house on higher ground and opting for raised foundations—between 60 and 90 centimetres high—to keep the structure above the water level.

To reduce the risk of flooding, it is also important that the land around the house is designed to drain water efficiently. The American Society of Landscape Architects suggests preserving natural ecosystems such as waterways, creating parks that manage water, and using green infrastructure such as transportation networks that cleanse and absorb flood water.

The St. Petersburg Pier in Florida has an elevated infrastructure. Credit: St Petersburg Pier

In particularly vulnerable areas, houses are built on stilts or floating platforms to keep them above water. Some houses in Thailand, for example, use steel pontoon platforms. It is also important that they have wind-resistant features, such as reinforced windows, to prevent damage from high winds.

The Tsunami House or how to protect your home from flooding

Even water-resistant houses are designed with the expectation that they might flood. To prepare for this, floors and walls are coated with special sealants, and critical components such as electrical installations, appliances and heating/cooling systems are elevated. One notable example is the curious "Tsunami House" located in Washington State. The ground floor windows are designed to break in the event of flooding, relieving pressure on the walls. The entire ground floor, including the furniture, is made of waterproof materials.

Flood-resistant materials include concrete, glazed brick, foam insulation, steel, treated wood, ceramic tile, waterproof adhesives and epoxy paint. One way to protect buildings against floods is to surround them with concrete walls or flood levees. Some companies offer flexible solutions, such as stackable structures filled with sand or gravel that can be quickly erected as a defence against water.

The Pérez Art Museum Miami uses porous soils, rain gardens and local vegetation to protect itself from water. Credit: ArquitectonicaGEO

The resilience of buildings is also critical because of the health impacts of flooding. Floods can cause injuries, drowning and exposure to contaminated water, increasing the risk of diseases such as diarrhoea, cholera and malaria. In the long term, floods can aggravate existing health conditions and have significant psychological effects. It is therefore essential to have infrastructure that can withstand such disasters.

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

The implementation of infrastructure and services in developing countries is often not particularly easy for companies or institutions from outside the country. And maintaining them isn’t easy either.

There are several important factors to consider when working toward economic, social, and health development in each region.
The first is the existence of a social cohesion structure. “There must be at least a basic social and political structure with a hierarchy and codes of conduct. The political structure must organize resources, distribute them, and promote a development strategy, stability, and future vision,” explains Ignacio Calatayud, president of HumanCoop, an NGO that works in development cooperation in Africa. Their working philosophy approaches community health through a One Health strategy, which aims to sustainably balance and optimize the health of people, animals, and ecosystems through training local personnel and building infrastructure.

“Political instability, corruption, and insecurity create obstacles that make it difficult to operate in a country,” says Calatayud.

Secondly, there must be a communication and energy infrastructure network around areas with water reserves and certain easily exploitable resources. “Cooperation between states to foster development in this area is important. Collaboration between different institutions—from the smallest local governments to the World Bank—is also key to supporting the maintenance of these structures, which attract investment to their countries,” affirms the president of HumanCoop.

 

The third important factor is adaptation to the local culture. NGOs like UPlanet serve as a bridge between technical knowledge—engineering, in this case—and local authorities and funding entities. “We must adapt our knowledge to the local culture. When a Western structure is introduced, there has to be someone with local knowledge to determine whether that technology can be implemented,” explains José Matías Fernández, president of UPlanet.

Volunteers who support organizations like HumanCoop or UPlanet are essential in maintaining water purification plants, self-sustaining agricultural systems, health centers, schools, and more. But without qualified local human capital, those infrastructures or services will fall into decline.
Recently, volunteers from the Sacyr Foundation—mainly engineers—participated in a cooperation project in Bir Mogrein (Mauritania, Africa).

Their goal was to help repair the town’s desalination plant, which is the community’s source of drinking water, improve the electrical installations of health and water infrastructure, develop a sanitation project at one of the schools, and launch a pilot project for drip irrigation using desalinated water—laying the groundwork for the region’s future agricultural project.

Ithar Association's cancer facility under development in Nouackchott, Mauritania

In this regard, a significant obstacle to working toward prosperous infrastructure in developing countries is the lack of human resources capable of managing the technologies, materials, or construction and maintenance techniques. That’s why continuous local human capital training is so important—and why conditions must be created to prevent brain drain.

The lack of cohesion among Western governments often hampers development cooperation in essential areas such as health, food, or industry in underdeveloped countries. “The globalization of Western ideas is declining. Governments are increasingly reluctant to collaborate. Development cooperation and humanitarian aid are two sides of the same coin, but they are not the same,” explains the president of HumanCoop. “We must help these countries, but at the same time, we must sow seeds for future progress. Otherwise, the work you’ve done today won’t be useful for the future, it’ll be just a short-term fix” Calatayud concludes.

Esta iniciativa nace con el objetivo de inspirar, compartir y sensibilizar sobre la innovación en todas sus formas. En cada episodio, abordaremos temas clave en el ámbito de nuestras áreas de negocio, con un enfoque divulgativo, riguroso y dinámico. 

En los dos primeros episodios, Marta Gil, Directora General de Estrategia, Innovación y Sostenibilidad de Sacyr charla con Ignacio Hernández, Director del Área de Instalaciones de la Dirección Técnica de Sacyr Concesiones. Juntos analizan como la innovación puede transformar las infraestructuras hospitalarias.

“Todo lo que es infraestructura sanitaria es un gran activo para la sociedad, pero consume muchos recursos. Por eso hay que hacerla más eficiente, algo que podemos lograr gracias a la innovación” explica Ignacio.

En esta charla, Ignacio explica la complejidad de los hospitales, unas infraestructuras muy diversas, en las que la interconexión de los diferentes sistemas puede mejorar su rendimiento global. 

Uno de los grandes protagonistas de estos episodios es el Hospital Cognitivo, un innovador proyecto impulsado por un consorcio liderado por Sacyr y aprobado por la Comunidad de Madrid. Este apasionante proyecto, en el que llevamos trabajando desde hace un año, tiene como objetivo desarrollar una plataforma de gestión integral de infraestructuras hospitalarias.

Entre los hitos más importantes alcanzados hasta ahora, destaca la creación del gemelo digital del Hospital del Henares (Madrid), donde se implantarán los avances conseguidos en este proyecto. “Gracias al gemelo digital, tendremos el edificio modelizado, de forma que podemos hacer actuaciones en un entorno virtual, evitando interrupciones en el funcionamiento del hospital. Podemos anticipar acciones, optimizar recursos y tomar decisiones basadas en datos, sin afectar la operatividad del hospital”, subraya Ignacio.

The extension of the L8 is already underway. This project will deliver three new stations—Gràcia, Clínic, and Francesc Macià—and will upgrade the existing Espanya station to accommodate the new alignment and increased passenger flow.

Toni Julià Ventura, Project Manager for the joint venture—comprising Sacyr (27.5%), Ferrovial (27.5%), Copcisa (22.5%), and Copisa (22.5%)—describes the initiative, promoted by the Generalitat de Catalunya, as a key milestone for sustainable mobility in Barcelona.
“With 19 million annual users, it is one of the most socially and economically impactful projects included in the Generalitat’s Infrastructure Master Plan,” explains Julià.

 

The works are divided into two main lots: Lot 1 involves conventional excavation techniques, due to the complex web of existing infrastructure in the area—such as Metro Lines 1 and 3—which makes the use of a tunnel boring machine (TBM) unfeasible. The extension will run from the current terminus, beneath Plaça Espanya and its central fountain, through a sequence of shafts and mined galleries.

Lot 2 begins in the logistics zone of Gran Vía, which hosts the TBM launch shaft. From this point, a 3.7-kilometer tunnel will be driven to connect the new stations at Hospital Clínic, Francesc Macià, and Gràcia. Emergency exits will be constructed at Consell de Cent and Muntaner.

The project is currently in its early stages, with approximately 10% overall progress. To date, most of the utility diversions have been completed, and hydromill (hydrofresa) retaining walls for the Consell de Cent emergency exit have been executed. Construction of the TBM launch shaft walls is ongoing.

In the coming weeks, excavation of the deep retaining walls at Hospital Clínic and Francesc Macià stations—each exceeding 80 meters in depth—will begin. Meanwhile, the TBM components are undergoing detailed inspection before assembly within the shaft. An acoustic enclosure will be installed over the shaft to mitigate noise and environmental impact during tunneling.

Once the main tunnel is completed, cavern excavation will commence. As the TBM bore accommodates only the twin tracks, the cross-section will be expanded through sequential mined phases to form the platform waiting areas and emergency access routes.

Key Figures

•    CO₂ Emissions Reduction: The extension between Plaça Espanya and Gràcia is expected to significantly reduce private vehicle use, saving CO₂ annually.
•    Tunneling Scope: Includes 3,728 meters of TBM-driven tunnel, 378 meters of cavern excavation, and 260 meters of mined tunnel.
•    Minimized Environmental Impact: The originally planned site footprint in Joan Miró Park has been reduced by 40%.
•    Stations and Infrastructure: The project comprises three new stations (Gràcia, Clínic, Francesc Macià), the adaptation of Espanya station, modified interconnection corridors, and two emergency shafts.
•    Contract Duration: The overall contract spans 58 months, divided into two main construction lots.