The 18-Story Subterranean Wonder of Anatolia

In 1963, a resident in the Turkish town of Derinkuyu in Cappadocia knocked down a basement wall during renovations and was stunned to discover an ancient secret passage. What he found was the entrance to an underground metropolis carved deep into the soft volcanic tuff rock, plunging over 85 meters (280 feet) beneath the surface.

**Derinkuyu** is the largest excavated underground city on Earth. It was capable of housing an estimated **20,000 citizens**, complete with livestock, food stores, schools, wine and oil presses, and chapels.

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Masterclass in Subterranean Engineering

- **15,000 Ventilation Shafts**:

A central 55-meter main shaft distributed fresh air throughout the complex while doubling as a secured well that could only be accessed from the inside, preventing invading armies from poisoning the water supply.

- **Colossal Rolling Stone Doors**:

Every corridor could be sealed from the inside by massive 1,000-kilogram circular stone doors (half a meter thick), each featuring a central hole designed for spears to repel intruders.

- **The 8-Kilometer Secret Tunnel**:

Ground-penetrating radar confirms that Derinkuyu was linked directly to neighboring Kaymaklı Underground City via an ancient 8-kilometer subterranean highway.