The ancient 18-level underground city in Turkey

As in a surreal horror film, the ancient underground city of Derinkuyu was discovered in modern times, when a man found a hidden room behind a wall in his house, which, after further excavation, was found to lead to an ancient underground complex, depth 18 levels.

The volcanic rocky landscape in its area Cappadocia in Turkey is full of many different underground cities, but perhaps none is as big or as impressive as Derinkuyu. This labyrinthine complex dates back to around the 8th century BC. and was probably built to serve as a shelter in times of war and invasion.

Its 18-level interior – deeper than any other underground complex found in the area – was literally an autonomous metropolis that included ventilation shafts, wells, kitchens, classrooms, olive mills, baths and even a winery, and could accommodate up to 20,000 people.

When threatened with attack, every level of the city could be sealed with one of the countless monolithic stone doors. Historians believe that the Hittites or Phrygians were among the first to rebuild Derinkuyu, but it was later occupied and expanded by a number of other groups, including Byzantine Christians, who left behind a collection of underground murals and chapels, reports history.com.

Today, over 600 entrances to the basement city Derinkuyu have been found in courtyards and private homes around it, giving the impression that there may have been some “holes” in this impressive defense, but it is doubtful that many enemies could penetrate the heavy and immovable stone doors of the city.

Despite the city’s long history, Derinkuyu was not discovered until the 1960s, when a local discovered the tunnels while renovating his house. Since 1969 the place has been open to visitors, with about half of the underground city accessible to them.