Derinkuyu, a subterranean city in Turkey

[Ellipse]

http://spi0n.fr/blog/photos-images-insolites/la-ville-souterraine-mysterieuse/

Quick translation:

Discover in 1963
Go under 85 meters (915 foots)
Can receive 10.000 inhabitants
Used as refuge by first Christians and frequent invasions

http://en.wikipedia.org/wiki/Derinkuyu_Underground_City

 

[sankara]

Very impressive indeed,

There is this link on Wikipedia:
http://www.nevsehir.gov.tr/ing_nevsehir_detay.php?id=111

 

[Laura]

One naturally wonders if this was originally built to survive cometary bombardment?

 

[Adaryn]

Another famous underground city in Turkey is Kaymakli.

Photos