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Cappadocia, Turkey - Located in central Turkey, the Cappadocia region is home to 36 underground cities! At a depth of approximately 85 m (280 ft), Derinkuyu is the deepest.

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Cappadocia, Turkey - Made up of seven underground levels, this city once housed up to 20,000 people.

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Cappadocia, Turkey - The city had everything for a civilization, including shops, living quarters, schools, ventilation shafts, wells, kitchens, oil presses, a bathhouse, storage rooms, and even primitive wineries.

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Cappadocia, Turkey - This maze-like city dates back to around the 8th century BCE and was a formidable defense against attack and invasion.

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Cappadocia, Turkey - In case of any threat, each level of the city could be sealed off using monolithic stone doors.

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Cappadocia, Turkey - Though Derinkuyu is home to the only cruciform church, there are an estimated 150 churches and several monasteries in Cappadocia.

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Cappadocia, Turkey - The city was discovered in 1963, when a local man reportedly stumbled upon some tunnels while renovating his home. It opened to the public two years later, though less than half is actually accessible.

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Matmata, Tunisia - Located in southern Tunisia is a small city made up of buildings called "troglodyte," or "cave-dweller" structures.

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Matmata, Tunisia - Over 2,000 inhabitants live there full-time.

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Matmata, Tunisia - The buildings were created by digging a big pit and carving out artificial cave walls to make a living space.

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Matmata, Tunisia - Though the underground complex was only rediscovered in 1967, it had already become quite famous.

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Matmata, Tunisia - Matmata's Hotel Sidi Driss was used in ‘Star Wars: A New Hope’ as Luke Skywalker’s childhood home on Tatooine.

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Matmata, Tunisia - The underground city was also featured in 'Attack of the Clones.'

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Petra, Jordan - An ancient caravan city tucked away in the mountains of southern Jordan, Petra may have once been home to 40,000 people at its peak about 2,000 years ago.

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Petra, Jordan - The ancient Nabataeans hand-chiseled the sandstone hillsides into an impressive collection of rooms, tombs, halls, and temples.

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Petra, Jordan - One of the most exquisite carvings is Al-Khazneh, or “the Treasury,” which features an ornamental facade that reaches 130 ft (40 m) up a rock face.

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Petra, Jordan - Petra is also known for its cameo in the film 'Indiana Jones and the Last Crusade.'

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Petra, Jordan - The subterranean dwelling was abandoned sometime around the 7th century CE, but it wasn't discovered by Europeans until the 1800s.

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Petra, Jordan - Excavators believe that the vast majority of Petra's ruins may still lurk underground.

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Coober Pedy, Australia - This small, underground town in Outback South Australia, known as the "opal capital of the world," houses around 1,600 residents below the surface.

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Coober Pedy, Australia - The dugouts and mines exist alongside homes, shops, restaurants, hotels, museums, churches, a casino, a gift shop, and even a local pub.

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Coober Pedy, Australia - Apart from the opal mines, Coober Pedy's homes were built underground to escape the scorching heat and to hide from the dingoes that roam the area.

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Coober Pedy, Australia - The town, which has one of the few underground churches in the world, produces more than 80% of the world’s opals.

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Coober Pedy, Australia - Despite its hard-working reputation, the town is also a cozy and friendly place to live.

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Matera, Italy - Sassi di Matera, which means "stones of Matera," is the area of prehistoric cave dwellings in the southern Italian city of Matera.

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Matera, Italy - The underground habitation was one of the first settlements of Italy, going back as early as 10,000 BCE.

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Matera, Italy - The houses, as this historical replica shows, are dug into the calcareous rock itself.

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Matera, Italy - Somewhat surprisingly, people still lived in the bare caves well into the 20th century—living with no access to amenities and very little access to sun.

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Matera, Italy - Soon, the low levels of light and high concentration of disease began to create slum-like conditions, and the residents struggled in poverty.

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Matera, Italy - Between 1953 and 1968, the cave-dwellers were moved into modern housing, but a more recent spike in tourism, and the flourishing of Matera's artistic community, have led to a reclamation of the land.

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Naours, France -

Two miles of tunnels and more than 300 man-made rooms rest some 30 m (100 ft) beneath a forested plateau in northern France.

The site was built around the third century CE as part of a Roman quarry, but it was later expanded into a subterranean village after locals began using it as a hiding place during the wars of the Middle Ages.

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Naours, France -

At its peak, Naours had enough room for 3,000 residents, and could provide many comforts like a chapel, stables, wells, and bakeries. 

The caves were sealed off for decades before being reopened in the 19th century as a tourist attraction. Visitors are treated to hundreds of pieces of graffiti left behind by Allied soldiers.

See also: The oldest continuously inhabited cities in the world

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