Derinkuyu, the Underground Turkish City That Housed 20,000 People

Introduction: an entire city carved beneath Cappadocia

A unique geology that made it all possible

The Cappadocia region owes its highly distinctive landscape to intense volcanic activity dating back several million years, which blanketed the terrain in successive layers of volcanic tuff, a rock soft enough to be carved by hand while remaining stable once exposed to open air over the centuries.

An accidental discovery in 1963

In 1963, a resident of the Turkish region of Cappadocia was carrying out simple renovation work on his house when he discovered, behind a wall, a passage leading to an underground network of completely unsuspected scale. This chance discovery would reveal to the world the existence of Derinkuyu, one of the largest underground cities ever uncovered, an architectural complex carved into the soft volcanic rock that geologically defines this unique region of central Turkey.

Archaeological excavations carried out in the following years revealed the truly staggering scale of this underground structure, which spans at least eighteen levels and reaches a depth of roughly eighty-five meters below the surface, a figure that still impresses archaeologists and visitors alike several decades after its official rediscovery by the relevant Turkish authorities.

A name that literally means deep well

The very name Derinkuyu, which literally means "deep well" in modern Turkish, directly reflects the nature of this exceptional site, seen for generations by local residents as a mysterious chasm long before its true scale was fully revealed by modern archaeological excavations beginning in the 1960s.

A capacity that defies the imagination

According to estimates from specialized researchers, Derinkuyu could house up to 20,000 people simultaneously, along with their livestock and food supplies, in the event of a major external threat. This considerable figure, worthy of a genuine underground city in its own right, reflects the remarkable level of sophistication achieved by the successive builders of this complex across centuries of continuous human occupation.

This exceptional capacity is explained by the presence of full infrastructure typical of a conventional urban settlement, including stables, chapels, wells, and sophisticated ventilation systems, allowing for prolonged collective life underground over potentially very long periods, far from any direct external threat facing the local population.

An architecture built for collective survival

A remarkably ingenious ventilation system

One of the most impressive aspects of Derinkuyu lies in its ventilation system, designed with remarkable ingenuity for such an ancient structure. More than fifty vertical ventilation shafts run through all the levels, ensuring constant air circulation down to the deepest parts of the complex, allowing residents to breathe normally even dozens of meters below the earth's surface.

These shafts also served an essential function in supplying drinking water, with some directly connected to natural underground springs. This dual function, ventilation and water supply, shows just how precisely the builders of this city anticipated the full range of basic needs for a population that might have to live in prolonged self-sufficiency far from the surface.

Giant stone doors to guard against intruders

To ensure the safety of residents in the event of an attack, each level of Derinkuyu could be sealed off using enormous circular stone doors, sometimes weighing several hundred kilograms, which could be rolled into place to completely block the narrow passages connecting the various levels of the underground complex.

This locking system, operable only from inside the structure, prevented any unwanted outside intrusion, offering formidably effective protection against potential attackers who might try to penetrate the underground network. This defensive architecture reflects a high degree of strategic thinking, worthy of the greatest surface fortresses built during the same historical period.

From Phrygian origins to Christian refugees

Origins dating back to the Phrygian era

The earliest excavations that gave rise to Derinkuyu are believed to date back to the era of the Phrygians, an ancient people who occupied the region of what is now central Turkey several centuries before our era. These early inhabitants are thought to have begun digging storage spaces and temporary shelters into the particularly soft and easily worked volcanic rock that geologically defines the entire Cappadocia region.

This volcanic rock, formed by ancient eruptions that blanketed the region in compacted ash over thousands of years, has a texture particularly suited to hand digging, while hardening enough on contact with air to offer remarkable structural stability, allowing for the construction of deep tunnels without major risk of collapse over the following centuries.

Major expansion in the era of the early Christians

It was, however, with the arrival of the first Christians in the region, fleeing Roman persecution and later other successive threats over the centuries, that Derinkuyu saw its most significant expansion. These religious communities considerably widened the existing network, adding numerous underground chapels, communal living spaces, and increasingly elaborate defensive systems to guard against potential hostile incursions.

This prolonged religious use explains the presence, still visible today, of numerous architectural features of a spiritual nature within the underground complex, reflecting several centuries of continuous occupation by communities seeking refuge far from prying eyes and the successive waves of persecution that marked the turbulent history of this region of Anatolia.

Derinkuyu today: world heritage and tourist attraction

A site connected to a vast regional underground network

Archaeological research conducted in recent decades suggests that Derinkuyu was not an isolated site, but was likely part of a larger network of interconnected underground cities across the Cappadocia region, the best known of which remains the neighboring city of Kaymaklı. Some tunnels discovered even suggest the existence of galleries potentially connecting several of these underground complexes across several kilometers of distance.

This hypothesis of an interconnected regional network remains the subject of active archaeological research, carried out notably by Turkish teams in collaboration with international institutions specializing in the study of ancient Anatolian heritage. This research could still reveal, in the years ahead, the existence of galleries and chambers currently unrecorded by archaeologists. Some researchers have even speculated that the full extent of this underground network, if it truly connects several known sites, could rival the footprint of a mid-sized modern town once mapped in its entirety.

Communal halls with multiple functions

Beyond simple living quarters, Derinkuyu also included vast communal halls intended for a variety of collective uses, including meeting spaces, storage areas for provisions, and even wine and oil presses carved directly into the rock, reflecting an organized economic and social life extending even into the depths of this extraordinary underground city.

Some levels also housed rudimentary schools and spaces dedicated to craftsmanship, suggesting that life in Derinkuyu was not limited to brief periods of occasional refuge, but could extend over periods long enough to require maintaining regular educational and productive activities within the underground complex itself, far from any direct natural light.

International recognition and growing tourist appeal

Today, Derinkuyu ranks among the most visited sites in the Cappadocia region, drawing tens of thousands of tourists each year from around the world to explore part of this exceptional underground network, now partially developed and secured to allow international visitors to tour it safely. Guides who lead tours through the site often note that visitors emerge with a very different sense of scale than they expected, having assumed beforehand that an underground settlement of this kind could only ever have been a cramped, temporary hideout rather than a functioning city.

The Cappadocia region, including its underground cities and its famous fairy-chimney rock formations, is inscribed on the UNESCO World Heritage List, an international recognition that reflects the exceptional and universal value of this unique architectural and geological heritage, jointly shaped by volcanic nature and human ingenuity across the ages.

Conclusion: an ancient feat of engineering that still fascinates

An exceptional testament to human ingenuity

The story of Derinkuyu strikingly illustrates humanity's ability to turn a geological constraint, the soft volcanic rock of Cappadocia, into a formidable architectural opportunity, capable of safely sheltering thousands of people during prolonged periods of crisis. This technical feat, achieved without the modern tools available to today's engineers, continues to draw admiration from specialists in ancient architecture around the world.

This site also continues to fuel ongoing archaeological research, with each new excavation campaign yielding further discoveries about the social, religious, and defensive organization of this extraordinary underground community, whose very existence remains, even today, partly mysterious to researchers who specialize in this complex historical period.

A lesson in humility before the genius of ancient civilizations

Derinkuyu is a powerful reminder that ancient civilizations, often underestimated by an overly modern view of human history, possessed technical knowledge and collective organization of remarkable sophistication, capable of meeting engineering challenges that continue to impress our contemporary societies, despite their access to infinitely more advanced technological tools. This underground city thus remains a lasting symbol of human resilience and inventiveness in the face of adversity, regardless of the era in question.

For architects and contemporary engineers, Derinkuyu still serves today as a surprisingly relevant source of inspiration, particularly in discussions around modern underground architecture, a discipline gaining relevance amid climate challenges and the growing scarcity of buildable space in certain densely populated urban regions. The principles of natural ventilation and passive thermal regulation observed at Derinkuyu even inspire certain contemporary architectural projects focused on reducing their overall energy consumption.

Finally, the site continues to play an important economic role for the Cappadocia region, with the cultural tourism generated by these underground cities contributing significantly to local income and to the long-term preservation of this exceptional heritage. This economic dimension, combined with the site's scientific and historical interest, guarantees continued protection of Derinkuyu for future generations of researchers and curious visitors from around the world. Few ancient sites manage to combine such a compelling survival story with such immediate, walkable proof of the engineering behind it, which may explain why Derinkuyu keeps drawing return visits from travelers who thought they had already seen everything Cappadocia had to offer.

By Maxime Marquette, columnist

Sources

Primary sources

UNESCO — World Heritage entry on Cappadocia

Turkish Ministry of Culture and Tourism — Official documentation on Derinkuyu

British Museum — Collections related to the history of ancient Anatolia

Secondary sources

National Geographic Travel — Reports on the underground cities of Cappadocia

Smithsonian Magazine Travel — Analyses of Derinkuyu's history

BBC Travel — Articles on the discovery and visiting of Derinkuyu