ISABEL RUBIO ARROYO | Tungsteno
Many modern cities conceal beneath their streets a vast network of secret tunnels that serve various purposes, ranging from former shelters and military command centres to historic ossuaries. Cities like Berlin, London, Paris, and New York reveal that urban life and history extend beyond the surface. Their depths hold a captivating heritage of wartime bunkers, espionage routes, and abandoned infrastructure.
Berlin
Berlin's tunnels have historically served as strategic refuges and military command centres, preserving stories from the Second World War through the Cold War. Several associations are dedicated to exploring and documenting these underground spaces, offering guided access to iconic air-raid shelters and bunkers. Their aim is to show how the city prepared for conflict and how these structures protected its inhabitants during times of crisis.
Beyond shelters, escape tunnels tell stories of ingenuity and resistance. More than 70 tunnels were built beneath the Berlin Wall, enabling some 300 people to flee from East to West. The city’s subterranean past also hides other disused infrastructure, such as abandoned railway tunnels and even former brewery warehouses.
During the Cold War, some tunnels were used as escape routes. Credit: DW Euromaxx
London
The Kingsway Exchange tunnels complex, which stretches across 8,000 square metres beneath High Holborn, was built during the Second World War to protect Londoners during the Blitz. Although it was never used for that purpose, the site hosted the Special Operations Executive (SOE), Winston Churchill's wartime espionage organisation. James Bond author Ian Fleming worked regularly with the SOE in this labyrinth of tunnels, which may have inspired Q Branch in his famous novels.
The tunnels remained strategically important after the war. During the Cold War, they functioned as a strategic communications hub. Following the Cuban missile crisis in 1962, the complex served as a relay point for the famous “red telephone” hotline between the Pentagon and the Kremlin. A government bunker was also built for use in the event of a nuclear attack. Today, there are plans to open the site to the public as a tourist attraction, featuring a military intelligence museum, an exhibition on espionage, and a bar marketed as “the deepest bar in the world in a city.”
The passages that protected London during the Second World War.
Paris
Much of the Parisian subsoil consists of nearly 200 miles (about 320 kilometres) of limestone quarries, originally excavated to build the city. Part of this network forms the Paris Catacombs, one of the largest ossuaries in the world. They contain the remains of some six million Parisians and have been dubbed "the empire of death." These abandoned quarries are sometimes visited illegally by "urban explorers," who have been known to organise secret underground nightclubs and cinemas.
Paris also boasts a complex sewer system spanning 1,662 miles (around 2,675 kilometres), modernised in the 19th century and historically used as escape routes for criminals. The metro network also includes four “ghost” stations closed since the Second World War. Other underground points of interest include a secret military bunker near the Eiffel Tower and the basement of the Opéra Garnier, which houses a real underground lake.
The catacombs of Paris lie 20 metres underground, with 243 steps and 2,000 metres of tunnels. Credit: Paris Musées
New York
In 2024, an illegal tunnel was discovered in Brooklyn, New York, beneath the Chabad-Lubavitch headquarters in Crown Heights, a busy Jewish site that welcomes thousands of visitors a year. The 60-foot (18-metre) tunnel was dug clandestinely and without structural reinforcements, causing destabilisation under the synagogue sanctuary. Due to safety concerns, New York City issued an emergency order to stabilise the building.
Illegal tunnel discovered beneath an historic synagogue in Brooklyn, New York. Credit: Eyewitness News ABC7NY
The evidence suggests the tunnel was constructed by a group of students known as the Tzfatim, who sought to expand the synagogue in accordance with the vision of their deceased leader, Rabbi Menachem Mendel Schneerson. When police arrived to inspect the tunnel, clashes broke out with members of the community. The altercation resulted in nine arrests on charges including criminal damage, reckless endangerment, and obstruction of government administration.
Tungsten is a journalistic laboratory that explores the essence of innovation.
