The Underground City — illustrated-library edition cover
VOL 4: ANCIENT MYSTERIES VERDICT: UNSOLVED

The Underground City

An Underground Refuge Built and Expanded Across Generations

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.

Derinkuyu was enlarged and reused over time. Its builders did not leave a dated plan, and assigning each level to a named people is uncertain. Only part of the complex is open to visitors.

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

Estimated capacity

Large capacity figures are estimates; rooms, storage and water access show how refuge was possible.

Hidden Entrances

Many entrances

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

The Evidence

An artist’s view of a round stone door with a small central opening.
ILLUSTRATED DOOR

The Rolling Stone Doors

An illustrated rolling stone door. The central opening is visible, but the picture alone cannot tell us every way it was used or how much the stone weighed.

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.

A measuring tape stretched across an illustrated rock surface.
SURVEY ILLUSTRATION

Investigating Construction Layers

An imagined survey of a rock surface. Different marks can prompt questions about tools and alterations, but this drawing supplies neither measurements nor a dated building sequence.

Rooms, passages and religious spaces reflect repeated use and enlargement. Carving style alone cannot assign every level to a named civilisation or a precise century.

Diagram connecting an underground refuge with ventilation shafts, a well, rooms and passages.
LIVING UNDERGROUND

The Underground Network

Air, water, space and movement: four needs of an underground refuge. The diagram connects questions to ask about Derinkuyu, rather than inventing a plan of its levels.

Shafts and passages helped make underground occupation possible. Their extent and proposed connections require surveys; a large network does not establish that every space was inhabited at once.

Three Thousand Years Underground

~1800 BCE

The Hittites Arrive

People in Cappadocia used workable volcanic rock for shelters and storage. Claims that a particular people began Derinkuyu at this date are uncertain.

~800 BCE

The Phrygians Build

Iron Age construction has been proposed for early phases, but the exact starting date and builders remain debated.

~370 BCE

Xenophon's Account

Xenophon described underground homes in Armenia after his journey in 401–400 BCE. This is useful comparison evidence, not a description of Derinkuyu.

2nd-3rd C.

Christians Expand

Christian communities used and altered underground spaces. Religious features provide evidence of use without identifying the date of every earlier excavation.

7th-12th C.

The Byzantine Fortress

Underground refuge was useful during periods of conflict. Christian spaces show later use, but do not date every passage or prove that a single expansion created the full complex.

1923

The Population Exchange

The 1923 population exchange displaced Christian communities from the region. That disrupted local knowledge, but does not establish that every entrance was forgotten at once.

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 Armenia, based on his journey in 401–400 BCE — over two thousand years before Derinkuyu was officially rediscovered.

The Modern Expert

Andrea De Giorgi

An archaeologist who discusses the region’s long history of rock-cut construction. Proposed Phrygian origins should not be treated as an agreed date for Derinkuyu’s deeper levels.

The Last Witness

Richard MacGillivray Dawkins

The linguist Richard MacGillivray Dawkins recorded sheltering at Axo in Cappadocia in 1909. This is evidence from another settlement, not an eyewitness account of Derinkuyu.

A man with a lantern and chickens at an imagined opening behind a wall.
An imagined version of the popular rediscovery story. The man, chickens and moment of discovery are storytelling details, not a documented photograph.

The Question That Remains

The city’s many phases make a single-builder answer unlikely. Its later religious spaces provide evidence of Christian use, while the date of its earliest excavation remains uncertain.

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 the key clues and competing explanations — 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

Desert drawings, undeciphered writing, and ingenious ancient machines. Discover what the evidence explains — and which questions remain open.

See all books in this volume →

Keep investigating

Check the evidence

What the evidence supports

Derinkuyu contains many underground levels with rooms for shelter, storage, worship and other needs.

Where to be careful

Its development involved more than a single building event. Popular population capacities are estimates, not an ancient census.

Explore the sources

These selected sources support this guide and offer further reading. Some are written for adults; explore them with a parent or teacher.

The story and illustrations are modern retellings. Imagined scene details are not historical evidence. These sources are a starting point, not citations for every narrative detail.

Evidence guide reviewed 8 September 2026.

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