Turkish man discovers 2000-year-old underground city while chasing chickens.

A Turkish man discovered an abandoned underground city, Derinkuyu, while chasing his chickens through a hole in his basement during renovations. The city, which was once home to 20,000 people, is the largest excavated underground city in the world and is believed to connect to more than 200 smaller, separate underground cities. Researchers found 18 levels of tunnels containing dwellings, dry food storage, cattle stables, schools, wineries, and even a chapel. The city was likely originally used to store goods, but was then used as a bunker to escape from foreign invaders. Derinkuyu was finally abandoned in 1923 by the Cappadocian Greeks, who faced defeat in the Greco-Turkish war and escaped to Greece.