Underground city of DERINKUYU

Several million years ago, volcanic eruptions spewed layer after layer of ash, called tuff or tufa. Over time the tuff cemented into a soft, easily carvable, yet relatively stable rock. Inhabitants of ancient Anatolia realized that they could carve out their homes right into the hillsides and underground. Derinkuyu is one of the many rock-cut dwellings in the region, however, it is the deepest one to date.