Seven Underground Cities: How to Explore Them

From impressive military hideouts to macabre tourist attractions, complex underground haunts lurk beneath cities around the world. These urban explorers’ paradise features endless tunnels, hidden chambers, and other secrets. Here, we investigate seven of the world’s famous underground cities.

Paris Catacombs

The sophisticated, romantic capital of France is unrivaled in its beauty, historic architecture, and artistic legacy. However, the streets of Paris hide a dark and disturbing past. In the 16th and 17th centuries, cemeteries became so overwhelmed with the bodies of the dead that rotting corpses encroached onto nearby properties. Their stench made living in Paris unbearable.

In the 1780s, officials moved six or seven million bodies from the overcrowded cemeteries into a series of 13th-century quarry tunnels. Thus, the Catacombs came into being. The walls, arches, sculptures, and other structures are entirely made of skulls, femurs, and other bones.

Paris Catacombs

Skull walls of the Paris Catacombs. Photo: Wyatt Rivard/Shutterstock


This grisly tableau of tunnels is 320km in total, with only 1.6km accessible to the public. Public visits began around 1867. Wandering around other, sealed-off tunnels is illegal. But this has not stopped urban explorers nicknamed “cataphiles” from giving the local police a hard time. Not surprisingly, even ravers like this venue for their parties.

Parisian police have issued fines to those breaking the law, as they have to organize search parties and dog teams to find those who get lost in the underground maze. In 2017, two teenage boys went missing for three days after straying from the visitor’s paths. When found via the search dog team, they had hypothermia.

The warning at the entrance to the Catacombs reads, Arrête! C’est ici l’empire de la Mort — “Stop! This is the empire of Death”. It does not seem to deter the curious. On the contrary, it might attract some of them.


Vladivostok Fortress Tunnels

After the Russo-Japanese War in the early 20th century, the city of Vladivostok became one of the most fortified cities in the world. The Russian military built a gargantuan fortress encircling the city. Built along the local hills, its 16 forts bristled with weaponry. Several kilometres of underground tunnels, which are around 24m deep, connected the forts. The labyrinth includes multiple galleries.

russian tunnel

One of the Vladivostok Fortress tunnels. Photo: Jerry Kobalenko


Yet the war never came to that part of Russia. The guns never fired a shot. During the Russian Revolution and until the 1920s, construction of the Fortress for general military reasons decreased significantly. It was demilitarized and generally abandoned.

However, the NKVD and the Red Army continued to use the tunnels until the 1940s. They contain bomb shelters, escape tunnels leading to the sea, a reservoir, cellars, soldiers’ barracks, kitchens, bakeries, and other treasures from the past.

Modern visitors often go to what’s called Fort #7 to enter the tunnels. Urban explorers have a field day here, and there is a dedicated group called the Vladivostok Diggers Club which conducts tours and helps preserve the fortress’s structural and historical integrity.

Dixia Cheng, China

Beneath bustling Beijing is an entire underground city dating back to the Cold War. Its name is Dixia Cheng, or “dungeon”, and is outfitted and ready for any kind of disaster. In the 1970s, tensions with Russia heightened the prospect of nuclear war. This prompted Mao Zedong to order the construction of a subterranean city. Over 300,000 citizens dug and carried rock and dirt out with their own hands. The city stretches out over 85 sq km and goes up to 18m deep.

Underground City China

Dixia Cheng in Beijing. Photo: Xiao Niao/Flickr


This underground city could house six million people. It also attempted to model ordinary life above. The network of chambers, tunnels, and rooms had bunk beds, doctor’s offices, shops, theatres, restaurants, schools, and even a roller skating rink and a silk factory.

The concrete walls, laden with Cold War propaganda and images of Mao, are allegedly strong enough to withstand a nuclear blast. Additionally, it had its own ventilation system, a mushroom farm, and food storage houses. It truly was a place where one could survive Armageddon. There are over 90 entrances, linking main cultural locations, including the Forbidden City and Tiananmen Square.

Although nuclear war never came to pass, locals used the underground city for hotels, businesses, and forms of entertainment. It opened in 2000 to tourists. Currently, it is closed for renovations.


Turkey’s Cappadocia region contains hundreds of underground cities. Derinkuyu happens to be the deepest and most intricate. It is capable of hiding 20,000 people within the tunnels and chambers carved out of volcanic rock. On the outside, the entrance looks almost completely hidden and easily missed.

The city contained everything necessary for survival. It had ample room not just for people but livestock, storehouses, rooms, schools, and churches. There were approximately 50 ventilation shafts and good insulation for colder periods.

underground city

Derinkuyu Underground City in Turkey. Photo: Pakhnyushchy/Shutterstock


It goes 85m deep with 18 stories. Supposedly, the Phrygians started digging the tunnels around the 8th century BC. The Christians developed its more complex construction, as they needed protection from raids and persecution in later centuries. All this changed when the 1923 population exchange between warring Greece and Turkey led to the city’s eventual abandonment.

The city is indeed a secret hiding place, as its entrance was only rediscovered accidentally in 1963, by a man renovating his home. A few years later, authorities allowed tourists to explore the city.

Other notable subterranean systems in the area include Kaymakli Underground City and Özkonak Underground City.

Wieliczka Salt Mine

In southern Poland, you will find the Wieliczka Salt Mine. A powerhouse in salt production from the 13th century until 2007, it also grew into an iconic cultural centre.

salt mine in Poland

The astonishing Wieliczka Salt Mine. Photo: Kanuman/Shutterstock


The mine’s tunnel network goes on for 287km and is 327m deep. Visitors only take a 3.5km tour. Throughout this enormous complex, there are remnants of the mine’s glory days as one of the top salt producers in Europe. It extracted over 200,000 tonnes of salt annually.

Over the years, miners decided to outfit the dreary and mainly grey-walled mine with elaborate wall art. Beautiful chandeliers made of rock salt and salt crystals illuminate some parts of the mine. You will find shafts, railways, horse mills, and multiple chapels, including the famous St Kinga’s Chapel and sculptures made of, you guessed it, salt! There are also several saline lakes.

New York City Secret Tunnels

If you are looking for subterranean adventures in the Big Apple, you can access some of the city’s abandoned subway lines and tunnels. Through special tours or even on your own urban expedition, you can see how New York’s underground network evolved…and stayed frozen in time.

Each underground spot offers something different. For graffiti enthusiasts, the Freedom Tunnel beneath Riverside Park is a free and open art museum. Whimsical images or messages cover the otherwise bleak walls. Efforts to repaint the tunnel have been to no avail. It has become a shantytown for the homeless.

Freedom tunnel NYC

Freedom Tunnel. Photo: Stuart McAlpine/Flickr


The Basilica of St Patrick’s Cathedral Catacombs in Soho is not as accessible to the public. You have to book a 90-minute tour by candlelight to journey through claustrophobic corridors, vaults, and gates and see some of the city’s historic yet deteriorating tombstones.

Moscow’s Metro-2

The popular name for Moscow’s secret underground tunnels — Metro-2  — was invented by a couple of journalists 30 years ago. But the tunnels themselves exist, according to ExplorersWeb contributor (and former Pravda reporter) Galya Morrell. She has been in them. She said that they were simply called spets-vetka, or “special line”.

The first network of tunnels was already built by the 16th century, during the time of Ivan the Terrible, says Morrell. Politicians used them to flee the centre of the city during the frequent civil uprisings of that era. The rulers of the day also stored their weapons and treasures there.

Then around 1947, during Stalin’s time, the network expanded vastly. Some tunnels opened into bomb shelters that were essentially underground cities that could hold thousands of people for years. A rail line went to one of Stalin’s dachas, or country homes, outside Moscow.

Not surprisingly, you could access these tunnels from the Kremlin. Morrell grew up partly in the Kremlin — her father was a high-ranking official during the final decades of the Soviet era — and she once received permission to visit the underground complex from there. A train runs from one of those tunnels to a small government airport on the outskirts of Moscow.

woman in red kerchief in flooded tunnel

ExplorersWeb contributor Galya Morrell reacquainted herself with Moscow’s tunnels two years ago. Photo: Galya Morrell


Ordinary Russians never had access to these tunnels, whose entrances were guarded by the KGB. However, there was a third network that, for a few years, drew urban explorers — the centuries-old sewage tunnels. “In the 1980s, criminals dumped the bodies of their victims there,” says Morrell. Even those tunnels are now off-limits.

Kristine De Abreu

Kristine De Abreu is a writer at ExplorersWeb.

Kristine has been writing about Science, Mysteries and History for 4+ years. Prior to that, Kristine studied at the University of Leicester in the UK.

Based in Port-of-Spain, Kristine is also a literature teacher, avid reader, hiker, occasional photographer, an animal lover and shameless ramen addict.