Imagine walking through an ordinary doorway and discovering an entire world hidden beneath your feet. There are underground cities with rooms carved into rock, tunnels built for wartime survival, and mines transformed into extraordinary works of art.

These places weren't created for the same reasons. Some offered protection from invaders, others provided valuable resources, and a few became homes or public spaces.

Here are 10 fascinating underground places that reveal how people have made life beneath the surface.

1. Derinkuyu Underground City, Türkiye

Narrow rock-cut passage and circular stone door inside Derinkuyu Underground City in Türkiye.

Beneath Cappadocia's unusual volcanic landscape lies Derinkuyu, an underground settlement carved into soft rock. Its passageways connect rooms, storage areas, ventilation shafts, a well, and a chapel.

The settlement was used as a place of refuge during periods of danger, including times of conflict and religious persecution. Eight levels have been opened to visitors, although the full extent of the complex is greater than the accessible area. Its earliest origins remain uncertain, so claims assigning the entire city to one precise date should be treated cautiously.

2. Kaymaklı Underground City, Türkiye

Narrow rock passage and carved chambers inside Kaymaklı Underground City in Türkiye.

Derinkuyu isn't Cappadocia's only underground settlement. Nearby Kaymaklı contains interconnected spaces carved into volcanic rock, including storage rooms and areas associated with everyday life.

The design helped inhabitants shelter underground when danger approached. Narrow passages and heavy circular stone doors could make movement difficult for intruders. Today, visitors can explore only part of the complex, which forms part of Cappadocia's UNESCO-listed cultural landscape.

3. The Cu Chi Tunnels, Vietnam

Concealed entrance to the Cu Chi Tunnels among tropical vegetation in Vietnam.

During Vietnam's wars, fighters expanded an extensive network of tunnels in the Cu Chi area near Ho Chi Minh City. The passages connected hiding places, meeting rooms, storage areas, kitchens, and medical facilities.

The tunnels provided shelter and helped fighters move through the area while avoiding detection. The network became an important part of the conflict's history. Some sections are now preserved for visitors, offering a glimpse into the difficult conditions faced by people who lived and operated underground.

4. Wieliczka Salt Mine, Poland

Salt-carved sculptures and chandeliers inside the underground Chapel of St. Kinga at Wieliczka Salt Mine in Poland.

Salt was once an enormously valuable resource, and generations of miners extracted it from Wieliczka, near Kraków. Mining began in the 13th century, eventually creating an immense underground network.

The remarkable surprise is what miners left behind: chambers, sculptures, and chapels decorated with salt carvings. The site is part of a UNESCO World Heritage property and illustrates centuries of mining technology and underground craftsmanship.

5. The Paris Catacombs, France

Human skulls and bones arranged along a limestone corridor in the Paris Catacombs.

Beneath Paris lies an ossuary containing the remains of millions of people. In the late 18th century, authorities began transferring bones from overcrowded cemeteries into former limestone quarries to address public-health problems.

The remains were later arranged into the bone-lined walls that visitors see today. Although the name “Catacombs” is often used for the underground tunnels throughout Paris, the public ossuary is only one part of a much larger network of old quarries.

6. Orvieto Underground, Italy

Ancient chambers and carved passageways beneath the historic town of Orvieto, Italy.

The hilltop Italian town of Orvieto hides a maze of underground spaces beneath its streets. Over centuries, people carved caves and passageways into the soft volcanic rock, creating places for practical activities and storage.

Some structures are associated with the ancient Etruscans, while others reflect later periods of the town's history. Exploring these chambers reveals how an underground landscape can preserve traces of daily life long after the world above has changed.

7. Coober Pedy's Underground Homes, Australia

Living room inside an underground dugout home carved into rock in Coober Pedy, Australia.

In the hot, dry Australian Outback, some residents live in homes excavated into the ground. Coober Pedy developed as an opal-mining town, and underground houses—known as dugouts—became a practical way to escape extreme surface temperatures.

These homes can include bedrooms, living rooms, and other familiar features of an ordinary house. The town also has underground churches and galleries. It is a striking example of people adapting their architecture to a challenging climate.

8. Montréal's Underground City, Canada
Indoor pedestrian corridor connecting shops and public transport in Montréal's underground RÉSO network.

Montréal offers a very different underground experience. Its RÉSO network connects shopping areas, office buildings, hotels, metro stations, and other destinations through indoor walkways.

The network expanded as downtown buildings and transport infrastructure became connected, particularly around the development of the city's metro system and preparations for Expo 67. Despite its nickname, it isn't one continuous underground city. It is a collection of connected indoor spaces that makes navigating winter weather easier.

9. Edinburgh's South Bridge Vaults, Scotland

Historic stone-vaulted chambers beneath Edinburgh's South Bridge in Scotland.

Beneath Edinburgh's South Bridge are stone vaults dating to the late 18th century. The bridge was built across a valley, and spaces beneath its arches were enclosed and used for storage, workshops, housing, and other activities.

Over time, conditions in some vaults deteriorated, and their history became linked with Edinburgh's poorer residents and underground folklore. They are sometimes described as an underground city, but that phrase exaggerates what they are: a series of vaulted spaces beneath the bridge and surrounding structures.

10. The Beijing Underground City, China

Concrete underground civil-defence passage illustrating Beijing's Cold War-era tunnel network.

During the Cold War era, Beijing developed an extensive civil-defence tunnel system intended to provide protection in the event of an attack. The project reflected fears of conflict and the desire to prepare urban residents for emergencies.

Although often called the “Underground City,” the tunnels were not a second city operating like the one above ground. Accounts of their size, facilities, and public accessibility vary, and many areas are not freely accessible. Treat dramatic claims about vast underground palaces or fully equipped hidden cities with caution.

Why did people build beneath the earth?

These ten places show that going underground was rarely just about hiding. People dug into the earth to find resources, protect communities, create cooler homes, preserve the dead, and build infrastructure that worked in their surroundings.

Some underground spaces became monuments to human creativity; others remain reminders of war, danger, and difficult living conditions. The most fascinating part is that many still exist beneath places we walk through every day.

The next time you visit an ancient town, a historic mine, or a modern city, remember: the story above ground may be only half the story.