The elaborate subterranean city was connected via stairways and passages, and even connected to other underground cities through tunnels that stretched for miles. It’s thought to have been initially built during the seventh and eighth centuries BCE, and was in continual, frequent use through the 12th century. Based on the church found on the fifth and lowest level, it seems the population was Christian, and probably used the city during wartime. The city was also used as a refuge from the Mongolian invasion in the 1300s and up through the 20th century for Christian people fleeing persecution. It was finally abandoned for good in 1923.
Most of Derinkuyu’s entrances are hidden, and each of the five levels can be closed off separately with huge stone doors. The room for livestock and food stores, as well as a 55-meter shaft used as a well, means the inhabitants planned to be able to stay there for a long time. There were even arsenals and escape passages in case things became desperate.
(via Sometimes Interesting)
When the city was rediscovered by that fateful renovation, it had almost been forgotten. Since then, it’s gained fame as the largest of the underground cities in the area.
After its rediscovery, the city opened to tourists in 1969. Today, about half the city is available to the public. There’s no news about what happened to its accidental discoverer, though we hope he got a new house.