READER BEWARE: I am moving most of this material to The Phrygians section of the Progeny of Jove page and will replace it with material (mostly a collection of best-of-breed YouTube videos) strictly about the underground cities. Until then, please excuse the mess.
Underground Cities
such as Derinkuyu, Kaymaklı, Mazi, and Özkonak. In Derinkuyu alone there were estimated to be as many as 20,000 people who survived; in Özkonak , 60,000 people. At least some of these underground cities were interconnected.
Kaymakli
There is an underground tunnel in the direction of the neighboring underground city of Derinkuyu (9 km to the south), although the tunnel has not been completely excavated. —Ancient Code
Just who first built the underground structures and when remains something of a mystery. Archaeologists suspect the Phrygians, Persians or 15th century B.C. Anatolian Hittites may be responsible, but since the caves are carved from natural rock, it is difficult to trace their construction to a specific date.Just who first built the underground structures and when remains something of a mystery. Archaeologists suspect the Phrygians, Persians or 15th century B.C. Anatolian Hittites may be responsible, but since the caves are carved from natural rock, it is difficult to trace their construction to a specific date. —From “Vast Underground City Found in Turkey May Be One of the World’s Largest“
Include Norşun Tepe
List of Underground Cities in Anatolia
All of these names link to their Wikipedia entries: