The Derinkuyu Underground City is an ancient multi-level underground city in the Derinkuyu district in Nevsehir Province, Turkey. Extending to a depth of approximately 60 m (200 feet), it is large enough to have sheltered as many as 20,000 people together with their livestock and food stores. It is the largest excavated underground city in Turkey and is one of several underground complexes found across Cappadocia.
It was opened to visitors in 1969 and about half of the underground city is currently accessible to tourists.
The underground city at Derinkuyu could be closed from the inside with large stone doors. Each floor could be closed off separately.
The city could accommodate as many as 20,000 people and had all the usual amenities found in other underground complexes across Cappadocia, such as wine and oil presses, stables, cellars, storage rooms, refectories, and chapels. Unique to the Derinkuyu complex and located on the second floor is a spacious room with a barrel vaulted ceiling. It has been reported that this room was used as a religious school and the rooms to the left were studies.
Between the third and fourth levels is a vertical staircase. This passageway leads to a cruciform church on the lowest (fifth) level.
The large 55 m (180 foot) ventilation shaft appears to have been used as a well. The shaft also provided water to both the villagers above and, if the outside world was not accessible, to those in hiding.