Derinkuyu Underground City

Carved from the soft volcanic tuff of Cappadocia, Derinkuyu descends at least 18 levels — roughly 85 metres — below the surface, with rooms for living quarters, stables, wine and oil presses, storage, chapels, and a network of ventilation shafts that supplied fresh air to every level. Massive circular stone doors, some weighing half a tonne, could be rolled into place from the inside to seal sections of the complex against intruders, and the city is estimated to have been able to shelter up to 20,000 people along with their livestock and food supplies for extended periods.

The complex was rediscovered in 1963 when a local resident, renovating his home, knocked through a wall into a hidden tunnel. Subsequent excavation revealed connections to other underground settlements in the region, including a tunnel reportedly linking Derinkuyu to the underground city of Kaymaklı, 9 kilometres away. The identity of its original builders is debated — candidates include the Phrygians of the 8th century BCE, who are credited with the earliest excavation, and early Christian communities who later expanded the complex as refuge from Roman and, much later, Arab raids. Large portions of the complex remain unexcavated.