Fall Asleep to the Mysteries of Derinkuyu’s Underground City

Beneath a modest town in central Turkey, 18 storeys descend into pale volcanic stone — roughly 85 metres below the surface, carved into tuff that was laid down by eruptions of Mount Erciyes and Mount Hasan between 9 and 3 million years ago. The underground city of Derinkuyu was rediscovered in 1963 when a resident knocked down a wall during home renovations and found a passageway leading into darkness. What lay beyond was enormous: stables for livestock, wine and oil presses, chapels with carved crosses, schools, food stores, ventilation shafts reaching the full depth of the city, water wells tapping groundwater independent of any surface source, and massive rolling stone doors weighing up to 500 kilograms that could be sealed only from the inside. The city could shelter an estimated 20,000 people for months. Only about half of it has been excavated. The question of who first carved it — Phrygians in the 8th century BCE, Hittites a thousand years earlier, or someone else entirely — remains genuinely unresolved.

The stone itself made it possible. Cappadocian tuff is soft when freshly exposed, carvable with bronze or iron tools, but hardens over weeks as calcium carbonate reacts with atmospheric carbon dioxide — a geological property that allowed ancient builders to hollow out room after room, level after level, with the cured stone above supporting the weight of everything that followed. The same formation produced the fairy chimneys of Göreme, the honeycombed cliffs, the rippled valleys. Underground, the temperature holds constant at 13 degrees Celsius year-round while the surface swings from minus 20 in winter to nearly 40 in summer. Successive civilisations occupied and expanded the city over at least two millennia — early Christians hiding from Roman persecution, Byzantine populations sheltering from Arab raids for months at a time, later communities during Mongol incursions — until the 1923 population exchange emptied Cappadocia of the Greek-speaking inhabitants who had maintained the cities within living memory, and the entrances were forgotten.

Tonight you descend through the narrowing spiral stairway into stone that was ancient before anyone carved it. Over 200 underground cities have been identified across Cappadocia, some connected by tunnels kilometres long, and in 2014 construction workers in nearby Nevşehir uncovered what may be an even larger city still being excavated. The plateau is still revealing what it holds. Down here the ventilation shaft draws its slow breath from 85 metres above, the rolling stone doors stand open in their worn tracks, the tuff keeps its constant temperature and its millions of years of silence, and you rest.