Derinkuyu is a town and district of Nevşehir Province in the Central Anatolia region of Turkey. According to 2010 census, population of the district is 22,114 of which 10,679 live in the town of Derinkuyu. The district covers an area of 445km2, and the average elevation is 1300m, with the highest point being Mt. Ertaş at 1988m.Located in Cappadocia, Derinkuyu is notable for its large multi-level underground city, which is a major tourist attraction. The historical region of Cappadocia, where Derinkuyu is situated, contains several historical underground cities, carved out of a unique geological formation. They are not generally occupied. Over 200 underground cities at least two levels deep have been discovered in the area between Kayseri and Nevşehir, with around 40 of those having at least three levels. The troglodyte cities at Derinkuyu and Kaymaklı are two of the best examples of underground dwellings.HistoryThe oldest written source about underground structures is the writings of Xenophon. In his Anabasis he writes that the people living in Anatolia had excavated their houses underground, living well in accommodations large enough for the family, domestic animals, and supplies of stored food. The first two floors of the Derinkuyu Underground City have been dated to this early period.