from wikkipedia: http://en.wikipedia.org/wiki/Derinkuyu_Underground_City Derinkuyu Underground City is located in the homonymous Derinkuyu district in Nevşehir Province, Turkey. It is on the road between Nevşehir and Niğde, at a distance of 29 km from Nevşehir. It was opened for visitors as of 1969 and to date, only ten percent of the underground city is accessible for tourists. Its eight floors extend at a depth of approximately 85 m. The underground city at Derinkuyu has 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[1]. Between the third and fourth levels is a vertical staircase. This passage way leads to a cruciform church on the lowest level. The large 55 m 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. First built in the soft volcanic rock of the Cappadocia region by the Phrygians in the 8th–7th centuries B.C according to the Turkish Department of Culture,[2] the underground city at Derinkuyu was enlarged in the Byzantine era. The city could be closed from inside with large stone doors. With storerooms and wells that made long stays possible, the city had air shafts which are up to 100 feet (30 m) deep. Derinkuyu is the largest excavated underground city in Turkey. The complex has a total 11 floors, though many floors have not been excavated. Each floor could be closed off separately. The city was connected with other underground cities through miles of tunnels. The city could accommodate between 3,000 and 50,000 people. The underground city of Derinkuyu was the hiding place for the first Christians who were escaping from the persecution of the Roman empire[4].[citation needed] Everything discovered in these underground settlements belongs to the Middle Byzantine Period, between the 5th and the 10th centuries A.D. The number of underground settlements, generally used for taking refuge and for religious purposes, increased during this era. The Christian communities in the region took refuge, closing the millstone doors, when they were subjected to Arab raids which started in the 7th century. The raiders, aware of the dangers awaiting them inside, tried to make the local people leave their shelters by poisoning their wells. Underground cities in Cappadocia generally had a number of features in common: rooms for food storage, kitchens, churches, stables, wine or oil presses, and shafts for ventilation. The underground city in Derinkuyu, which covers eight levels and extends to a depth of 85 meters, was large enough to shelter thousands of people together with their livestock and food stores just pitty of al that 'graffiti' TFV