Beneath the cobbled roads of Derinkuyu in Turkey, there lies an ancient warren of tunnels and chambers that could have once accommodated as many as 20,000 people. Burrowing more than 85 meters (280 feet) beneath the Earth's surface and encompassing 18 levels, the Derinkuyu underground city is the world’s largest subterranean city – or, at least, the largest that's ever been discovered.
This labyrinthine complex under Derinkuyu is actually just one of a series of underground cities found in and around the Nevşehir Province of central Turkey, which are part of a UNESCO World Heritage Site. Another collection of underground towns can be found in nearby Cappadocia, just over 30 kilometers (18 miles) to the north, but Derinkuyu is the biggest and most visited.
Visitors to the town are told that Derinkuyu's underground history was only "rediscovered" in 1963 by a local man who kept losing his chickens. After noticing his poultry slip into a small crevasse during a renovation of their house, they unearthed a dark passageway that led to the complex. It was eventually revealed that hundreds of private houses in the town contained similar hidden passages leading to the subterrestrial settlement.
Amid the weaving nooks and crannies of the complex, there are rooms that were once used as a meeting hall, stables, kitchens, storage areas, living spaces, and a mini-prison. It even features a surprisingly efficient ventilation system that allows fresh air to circulate deep into the pits of the maze-like structure.
The Derinkuyu underground complex was never home to a strange community of mole people, despite its appearances. Throughout its long history, it primarily served as a refuge from war or periods of hardship but isn’t thought to have been continually inhabited for extended periods.
The age of the city is hotly debated with a broad range of estimates, but some reckon that work at the site might have started by the Phrygians up to 2,800 years ago. It’s more certain that the underground tunnels were used by the Persian Achaemenid Empire, founded by Cyrus the Great in 550 BCE, where it was used as a refuge for local townspeople fleeing war.
The clearest evidence come from the inscriptions, chapels, and alterations to the complex, which shows it was occupied by Greek-speaking Christians during the early days of Christianity. It was then used as a hide-out for Muslim Arabs during the Arab-Byzantine Wars between 780 and 1180 CE, before providing a sanctuary for Christians once again in the wake of the Mongolian invasions in the 14th century CE.
There are even some accounts that the complex was used as a shelter as late as the 20th century. Richard MacGillivray Dawkins, a British linguist who was studying Cappadocian Greek in the area, said that many people hid within mysterious underground tunnels when they caught news of the Adana massacre in 1909.
In the 21st century, however, the Derinkuyu underground city is merely a tourist hotspot that visitors are welcome to see.