Originally known as Elengubu, the ancient city of Derinkuyu in Turkey stretches across 18 levels of tunnels underneath the overground city of the same name - making it the largest excavated ...
A man from Derinkuyu, in the Nevsehir province of Turkey was renovating his basement. Using only a sledgehammer, he broke through one of his walls; and felt cool air coming in from the other side.