The under­ground city is a set of rooms locat­ed on 8 floors, and inter­con­nect­ed by var­i­ous tun­nels. The depth of Derinkuyu is more than 60 meters, and his­to­ri­ans and archae­ol­o­gists believe that about 20 thou­sand peo­ple lived in the city at cer­tain peri­ods. In addi­tion, Derinkuyu has stor­age facil­i­ties for grain and live­stock. The under­ground city exists thanks to a spe­cial soft rock — tuff.