Some of the most interesting cultural riches in Cappadocia are the 150-200 known undergruond cities of varying sizes.

I visited
Derinkuyu and Avanos but not the others.

http://cappadociatraveltours.com/sf-articles-of-Kown_Underground_Cities-tp-4_8.htm

I would love to visit these underground cities..so interesting. I wonder how many are out there still undiscovered.