Derinkuyu is 26km (16 miles) south of Nevsehir; Kaymakli is 18km (12 miles) south of Nevsehir

While the idea of a prehistoric people seeking shelter in caves is not a foreign one, it's startling to have discovered a system of underground cities as sophisticated as those found in Cappadocia. Over 200 underground cities at least two levels deep have been discovered in the area between Kayseri and Nevsehir, with around 40 of those comprised of at least three levels or more. The troglodyte cities at Derinkuyu and Kaymakli are two of the best examples of underground dwellings.

It remains a mystery as to who first started the digging, although Hittite artifacts found around the caves -- and the fact that many of the towns' names go back to the Hittite or Sumerian language -- suggest they were inhabited as far back as 3,000 to 4,000 years ago. The early Christians probably sought temporary shelter from the persecution of Roman soldiers; and after the 6th century, these dwellings provided protection from raiding Arab tribes. The crude carving of the surface levels of rock give way to a smoother, more refined face, which indicates that the levels were carved by different people at different times.

Each rock settlement had access to the safe haven of these underground dwellings by way of a secret underground passageway that would provide swift and unseen escape in times of emergency. In fact, an access tunnel can still be found on just about every villager's property. Additionally, the underground cities of Derinkuyu and Kaymakli, about 9km (5 2/3 miles) apart, are believed to be connected by an underground tunnel.

Every crucial entry point into the city was either camouflaged or blocked by a keystone, a large stone wheel that, once fixed in place, was immovable. Keystones were fixed at every level of the city as well. The labyrinth of tunnels and blind passageways hundreds of feet below the ground give shocking testimony to the tenaciousness of a civilization to survive and prosper by sentencing itself to months of existence deep within the earth.