In 1963, a man in the Nevşehir Province of Turkey knocked down a wall of his home. Behind it, he discovered a mysterious room. The man continued digging and soon discovered an intricate tunnel system with additional cave-like rooms. What he had discovered was the ancient Derinkuyu underground city, part of the Cappadocia region in central Anatolia, Turkey.

via Derinkuyu & The Underground Cities of Cappadocia | Sometimes Interesting.