A vast underground city carved into rock, with narrow tunnels, arched doorways, and soft lantern light
VOL 4: ANCIENT MYSTERIES VERDICT: UNSOLVED

The Underground City

Someone Carved a City 85 Metres Underground for 20,000 People. But Who?

Built ~800 BCE
Found 1963
Difficulty Standard
Chapters 9
INVESTIGATE

In 1963, a man in central Turkey knocked down his basement wall during a renovation. Behind it, he found a steep tunnel carved from solid rock — leading down into darkness. That tunnel opened into an underground city at least eight levels deep, with rolling stone doors, ventilation shafts, churches, schools, and stables.

It could hold twenty thousand people. It had been hidden beneath a quiet Turkish town for decades. And nobody could agree on who built it — or exactly when.

The Hittites left artefacts in the upper levels. The Phrygians had the skills to carve it. The Christians expanded it. The Byzantines perfected it. But the full truth may never be known — because ninety per cent of the city remains unexplored.

The Mystery

Derinkuyu

An underground city in Cappadocia, Turkey, carved from volcanic tuff rock over thousands of years by multiple civilisations. Rediscovered in 1963 when a man broke through his basement wall and found a tunnel that led 85 metres underground.

Depth

85 metres

Eighteen storeys deep — taller than most buildings, but going down.

Capacity

20,000 people

With livestock, food stores, wine presses, and water wells.

Hidden Entrances

600+

Concealed behind bushes, in courtyards, and inside people's homes.

The Evidence

A massive circular rolling stone door blocking an underground passage
THE DEFENCE

The Rolling Stone Doors

Circular discs of rock weighing up to 500 kilograms — openable only from the inside. Each floor could be sealed independently. Small holes allowed defenders to thrust spears at attackers while keeping the door shut.

Carved rock walls showing different construction styles across levels
THE LAYERS

The Construction Layers

Upper levels show rough Bronze Age carving. Deeper levels show precise Iron Age techniques. Christian sections contain crosses and Greek inscriptions. Each layer tells a different story about a different civilisation.

Cross-section illustration of Derinkuyu's underground levels
THE CITY

The Underground Network

Over 50 main ventilation shafts, 15,000 smaller air channels, a well reaching 55 metres deep, and a tunnel connecting to Kaymakli — another underground city kilometres away. This was not a hiding place. It was a civilisation.

Three Thousand Years Underground

~1800 BCE

The Hittites Arrive

The Hittites settle in Cappadocia and discover that the volcanic tuff rock can be carved with simple tools. They dig the first storage tunnels and shelters.

~800 BCE

The Phrygians Build

After the Hittite Empire collapses, the Phrygians — master Iron Age rock-carvers — begin the first major underground construction at Derinkuyu.

~370 BCE

Xenophon's Account

The Greek soldier Xenophon writes the oldest known description of underground dwellings in Cappadocia: "spacious below" with tunnels for animals and ladders for people.

2nd-3rd C.

Christians Expand

Early Christians fleeing Roman persecution arrive in Cappadocia and significantly expand the underground complex, adding chapels with crosses and Greek inscriptions.

7th-12th C.

The Byzantine Fortress

During centuries of Arab-Byzantine wars, the city is deepened to its full extent. Churches, a missionary school, and the tunnel to Kaymakli are added.

1923

The Population Exchange

Christian communities are expelled from Turkey. The people who knew the underground cities leave — and within a generation, the entrances are forgotten.

1963

The Rediscovery

A man knocks down his basement wall and finds a tunnel leading to a vast underground city at least eight levels deep. Derinkuyu is rediscovered.

The People in This Story

The Ancient Witness

Xenophon of Athens

A Greek soldier who described underground dwellings in Cappadocia around 370 BCE — over two thousand years before Derinkuyu was officially rediscovered.

The Modern Expert

Andrea De Giorgi

Associate Professor at Florida State University. A leading expert on Derinkuyu's construction, who credits the Phrygians as the primary builders of the deeper levels.

The Last Witness

Richard Dawkins

A Cambridge linguist who documented people sheltering in the underground cities as recently as 1909 — among the last recorded uses before the population exchange.

A lantern-lit tunnel carved deep into volcanic rock
Only 10% of Derinkuyu has been explored. Over 200 underground cities exist in the region. The mystery is far from solved.

The Question That Remains

The Hittites started digging. The Phrygians built deeper. The Christians expanded. The Byzantines perfected. And the people who could have told us the full truth were forced to leave in 1923.

Who truly built Derinkuyu — and when a mystery has been carved into by so many hands over so many centuries, is it even possible to give a single answer?

Read the full book to investigate every piece of evidence — then decide for yourself.

The Underground City book cover

Get the Full Book

The complete Derinkuyu mystery. 9 chapters of evidence, theories, and a question only you can answer.

9 Chapters Ages 8-12 DRM-free EPUB

Part of the Ancient Mysteries Volume

Giant drawings visible only from the sky. Books written in languages nobody can read. Machines that shouldn't exist. Real artefacts — no explanations.

See all books in this volume →