Hollow Earth: From Real Underground Cities to Agartha and the Rumored Polar Entrances

In 1963, residents of Derinkuyu in central Turkey accidentally opened a route into underground rooms. There, a round stone door can be rolled across a passage to stop anyone entering. Behind such doors lies Derinkuyu: rooms, wells, food stores, animal spaces, ventilation shafts, and several levels cut into rock. A person standing above ground may see only a small opening. The rest lies below, dark and concealed enough for a community to hide from war for a long time.