Derinkuyu and Kaymakli

The underground cities of Cappadocia have excited the imaginations of travelers since the Greek mercenary leader/historian Xenophon wrote about them in the 5th century BC. Hittite artifacts discovered in some suggest they may have been initially constructed a millennium before, but no one really knows for sure who dug the cities, or when, or why. The underground networks were certainly modified and probably also significantly expanded later by the early Christians who inhabited them. Some of these complexes are merely passages between different belowground dwellings. Others really deserve the title of "city": the largest, including Kaymakl? and Derinkuyu, have multiple levels and were equipped to house thousands of people for months at a time. The impermeable tufa, or porous rock, kept the insides of the cities dry, while ventilation shafts supplied air and interior wells provided water. Ground-level entrances were cleverly disguised, and in the event that invaders did make their way in, huge, round stones resembling millstones were used to block off different passageways and secure the city.