Why Is There a Massive Ancient City Hidden Beneath Turkey?

In 1963, a Turkish resident who simply wanted to expand his house ended up making an unexpected and monumental discovery. While knocking down a wall in his basement, he found a mysterious room—then another, and another. Without realizing it, he had uncovered the entrance to Derinkuyu: an underground city capable of housing up to 20,000 people beneath the ground of Cappadocia.

What appeared was “a stone iceberg.” That’s how Roberto Bixio, founder of the Genoa-based Centro Studi Sotterranei, describes the largest underground city of the ancient world. “The part that extends below ground level is, on average, between six and 10 times deeper than the height of the above-ground buildings of ancient Malakopea [in the same area]," he explains. Today, this site is known in Turkish as Derinkuyu, meaning "deep well."

The name is no exaggeration. Derinkuyu’s origins may date back to around the eighth century B.C., with successive civilizations expanding it through at least the Byzantine era. The result is a vast underground complex with rooms, stables, cellars, tombs, schools and even churches with refectories. It descends to a depth of about 280 feet and is organized on at least 18 levels. Some of these spaces continued to be used until the 19th century before Derinkuyu fell into oblivion.

Peace was not the norm in this part of the world. What is now central Turkey was the center of the Hittite Empire and, later, part of the Phrygian, Assyrian and Persian empires. It was then conquered by Alexander the Great and became an important Roman and Byzantine province. Between the seventh and 10th centuries A.D., it suffered Arab incursions and in 1175 it fell to the Seljuk Turks. Finally, it was absorbed by the Ottoman Empire from the second half of the 15th century onward.

The choice to build Derinkuyu was strategic but also geological. In need of defense, inhabitants of this area discovered that the rock there could be easily excavated and carved. The volcanic tuff that dominates Cappadocia—a porous rock formed from ash—is soft enough to be worked with relative ease but stable enough to support large underground cavities without the need for additional reinforcement. In Greek, malakos means “soft,” so Malakopea is likely a reference to the nature of the local stone. 

More than 360 ancient underground settlements have been geolocated in Cappadocia, spread across a vast area of volcanic tuff covering more than 7,700 square miles, at an average altitude of 3,300 and 4,900 feet above sea level. Derinkuyu, located in the province of Nevşehir, stands out as an exceptional case. At about 4,480 feet above sea level, it descends into volcanic formations beneath the town’s terrain.

The city was organized in layers, unfolding in a spiral around a large central shaft. Near the surface, where the entrances are hidden—often concealed within masonry houses—were the most functional spaces: storage areas, stables, armories and small churches. 

As one descends, rooms appear on different levels, connected by tunnels that function as veritable underground streets. In the two best-documented sectors, this network extends for more than 1.5 miles. Some of these passages are now blocked to prevent visitors from getting lost in a labyrinth where it is easy to become disoriented. Other sections are extremely narrow and steep; they force one to advance by crouching and lead to small chambers where, in another time, enormous stone doors were likely operated for defense.

The deepest rooms served as a last refuge in case of attack. Water was drawn from the water table through service wells, while air circulated through the main shaft connected to the surface, along with more than 50 additional ventilation shafts.

“An organization of this type, in addition to its residential function, had a clear defensive purpose: it served as a refuge against incursions and, in case a sector was taken by attackers, it allowed the isolation of entire sections, easy movement, coordination of aid between different points or even the organization of counterattacks through alternative passages,” explains Bixio.

Not everyone, however, has interpreted its origins the same way. In the 1980s, Swiss writer Erich von Däniken visited Derinkuyu and concluded that a structure of such complexity could only be explained as protection against attacks “from the air.” He even suggested the involvement of extraterrestrial visitors in its construction.

Beyond such fantastical interpretations, historical evidence points elsewhere. The underground city was likely used for centuries by different populations seeking refuge from invasions and from a climate marked by harsh winters and intense summers. It's remarkable that this excavated architecture, conceived centuries ago, has not only withstood the passage of time but can still be explored today.