Derinkuyu
Türkiye · not visited
Eighty-five metres down, room for twenty thousand people and their livestock, and fifty ventilation shafts arranged so that no two openings ever line up.
- Latitude
- 38.3739° N
- Longitude
- 34.7350° E
- Depth
- c. 85 m
- Levels
- 8 open, c. 18 estimated
- Open questions
- 4 logged
What is actually there
In 1963, a man in the Turkish town of Derinkuyu knocked down a wall in his basement during renovations and found a room behind it. Then another. What he had opened was the entrance to the largest excavated underground city in Turkey, descending roughly 85 metres into the volcanic rock beneath Cappadocia.
Eight levels are open to visitors. Estimates for the full extent run to eighteen. The complex includes stables, communal kitchens, wine and oil presses, storage rooms, chapels, a cruciform church on the lowest accessible level, wells, and what has been identified as a religious school. Capacity estimates put it at up to 20,000 people together with their livestock and food stores.
This was not a place to live. It was a place to disappear into.
The defensive design makes the purpose obvious. Circular stone doors, some weighing around 500 kilograms, could be rolled across passageways from the inside by one person and could not be moved from the outside. Corridors are narrow enough to force attackers into single file. The whole thing is a city-sized refuge, built to hold a population out of sight for weeks.
The engineering nobody photographs
The most impressive feature at Derinkuyu is invisible, and it is the reason the place worked at all.
More than fifty vertical ventilation shafts pull fresh air down through every level. The main central shaft, roughly three metres by two point eight, connects multiple floors, and the openings of different levels are deliberately offset so that no two ever overlap, a layout that reads as engineered specifically to maximise airflow rather than as a by-product of digging. The system still works: the temperature holds steady at around 13 to 15 degrees year-round, and you can feel moving air in the corridors today.
Keeping twenty thousand people and their animals breathing, eighty-five metres underground, for weeks, without mechanical assistance, is a harder problem than carving the rooms. The rock is soft volcanic tuff and cuts relatively easily. The air does not.
What is still open
Who dug the first tunnels, and when?
The Turkish Ministry of Culture and most archaeological summaries favour the Phrygians, in the eighth to seventh century BCE. Others have proposed the Hittites, which would push the earliest phases back to roughly 2000 to 1000 BCE. Some accounts attribute the whole thing to early Christian communities in the first centuries CE. What is not in dispute is that Byzantine Christians vastly expanded it during the Arab-Byzantine wars of the seventh to tenth centuries.
Here is the part worth being precise about: the early dating rests on regional history and on when populations are known to have been in the area, not on radiocarbon dates from the tunnels themselves. Carving rock leaves nothing organic to date directly. That is a real limitation, and it means the earliest phases are genuinely less firmly dated than the later ones.
How much is still unexcavated?
Eight levels are accessible, eighteen are estimated. Cappadocia contains more than thirty known underground settlements, around forty with at least two levels, and tunnels are thought to connect some of them, including a reported passage of several kilometres linking Derinkuyu to nearby Kaymaklı. The full extent of the network has never been comprehensively mapped.
Was the ventilation designed or discovered?
The offset shaft layout looks deliberate, and specialists describe it as such. Whether that arrangement was worked out in advance or arrived at by generations of trial and correction, with later diggers fixing the airflow problems of earlier ones, is not something the rock itself can tell you.
How many more are there?
Derinkuyu was found by accident by a man renovating his house. Cappadocia is riddled with soft tuff, and new underground spaces continue to turn up during construction work. Nobody can say how much of the region remains hollow and unrecorded.
We know why Byzantine Christians used Derinkuyu: they were being raided, and there are written records of it. What we do not have is a reason for the first excavation, whoever did it and whenever that was.
What if the impulse to go down, this far down, was not a response to any one invasion but a much older habit in this landscape? Soft rock invites carving, and people in Cappadocia have been cutting homes, stores and churches into it for millennia. What if Derinkuyu is less a single defensive project than the accumulated result of three thousand years of people repeatedly deciding that the safest place to be was under the ground, and each generation finding the tunnels their ancestors left and going deeper?
That would make the city not an engineering achievement so much as a very long memory of fear, written into rock.
Sources
- Turkish Ministry of Culture and Tourism, official dating and description of Derinkuyu.
- Aydan, Ö. and Ulusay, R., published engineering assessment of the Cappadocian underground structures, including the ventilation shaft layout.
- Bixio, R., Centro Studi Sotterranei, Genoa, survey work on Cappadocian underground settlements.
- Published acoustic and architectural studies of the central ventilation shaft system.
Not visited in person. Written from published sources. Last reviewed September 2026.