They Built An Entire City Underground — And Hid 20,000 People Inside For 1,000 Years

Added: 2026-05-27

Derinkuyu Underground City in Turkey is the largest underground city ever discovered, housing 20,000 people for over 1,000 years beneath the surface. Carved by hand into volcanic rock 85 meters underground, this 18-story city featured complete urban infrastructure including churches, schools, stables, kitchens, grain silos, and wine cellars. The city was designed for defense, with massive 1,000-pound stone doors that could be sealed from the inside, making it impervious to enemy forces. The inhabitants remained hidden from invaders including Romans persecuting Christians and Arab raiders attacking Byzantine villages. The city was forgotten in 1923 and rediscovered in 1963 when a man accidentally knocked down a wall and found the tunnel leading to this remarkable underground civilization.