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 ...

Located in modern-day Turkey, the ancient underground city Derinkuyu spanned seven levels, with four main ventilation channels and over 50,000 other smaller shafts. Researcher Sezin Nas re-created ...