In 1963, a man in central Turkey was trying to solve a very ordinary problem. His chickens kept disappearing. They would wander into a small crack in the wall of his basement and never come back. Naturally, he assumed the hole led somewhere outside. Maybe a fox den. Maybe a tunnel in the rock.

So he grabbed a tool and broke through the wall. What he found on the other side wasn’t a tunnel. It was a doorway.

Behind it stretched a network of dark corridors carved deep into the earth. The passages led to rooms. The rooms led to stairways. The stairways led to more levels underground.

Eventually archaeologists realized something unbelievable: This was not a cave. It was an entire underground city.

The place is called Derinkuyu Underground City and at its peak, it could shelter around 20,000 people.

Families. Livestock. Food stores. Churches. Schools. Entire communities lived here, hidden beneath the surface of the Earth. And until a random homeowner knocked down a wall in his basement, the modern world had no idea it existed.

A City Hidden Beneath Cappadocia

The underground city sits beneath the strange and beautiful region of Cappadocia — a landscape famous for its fairy-chimney rock formations and cave dwellings. But beneath those surreal hills lies something even more remarkable.

Derinkuyu plunges about 85 meters underground, forming a maze of tunnels and rooms that descend through multiple levels. Archaeologists have identified 18 different floors within the underground complex.

Only a portion of them are open to visitors today. And yet even that small portion is enough to make one thing clear: This was not a hiding spot. It was a functioning city.

Inside the underground settlement were living quarters for families, kitchens and food storage rooms, wine presses and oil presses, stables for animals, churches and religious spaces, schools and gathering halls, ventilation shafts and water wells

Everything needed for long-term survival existed underground. Which raises an obvious question: Why would anyone build a city beneath the Earth in the first place?

To understand why Derinkuyu exists, you need to understand the history of this region.

For thousands of years, central Anatolia sat at the crossroads of empires. Armies passed through constantly. Invasions were not rare events, they were recurring ones. Villages could be destroyed in a matter of hours.

So the people who lived here came up with an unusual solution: Instead of building higher walls… They built deeper shelters.

Entire communities carved tunnels into the soft volcanic rock beneath their homes. When danger approached, they could disappear underground.

Entrances were sealed. Torches were lit. Life continued below the surface. From the outside, the village looked empty. But beneath the ground, thousands of people waited in silence.

The Engineering of the Underground City

One reason the underground city exists at all is the unique geology of Cappadocia. The region is made of a soft volcanic rock called tuff. Tuff is easy to carve using simple tools, but once excavated it becomes surprisingly stable.

Ancient builders took advantage of this natural material. Generation after generation expanded the underground spaces. Rooms became corridors. Corridors became tunnels.

Eventually, the tunnels formed a vast underground network. But digging rooms underground is only part of the challenge. If thousands of people are going to live beneath the surface, they need something even more important: Air.

Derinkuyu solved this problem with a remarkably advanced ventilation system. More than 50 ventilation shafts run from the deepest levels all the way to the surface. These shafts circulate fresh air throughout the entire underground city.

Even today, visitors walking through the tunnels can feel cool air flowing through the corridors. That airflow kept the underground population alive. Without it, the city could never have functioned.

Defense was the entire point of the underground city. So its builders designed the tunnels to be extremely difficult for invaders to navigate. Many of the corridors are barely wide enough for one person.

If attackers managed to enter the city, they would have to move slowly and in small numbers. Meanwhile, the defenders had another advantage: Massive circular stone doors.

These stone slabs functioned like giant rolling barriers. Each one could be pushed into place to seal off a tunnel. Once closed, the doors could only be moved from the inside.

If enemies broke into the first section of the city, the residents could retreat deeper underground and seal another barrier. Level by level. Tunnel by tunnel. The city effectively became a multi-layered fortress hidden beneath the earth.

Who Built Derinkuyu Underground City?

The origins of the underground city remain a topic of debate among historians. Many researchers believe the earliest tunnels may have been dug by the Phrygians, an ancient civilization that lived in the region during the first millennium BCE.

Later civilizations expanded the underground network. But the city became especially important during the time of the Byzantine Empire.

During this era, Christian communities in Anatolia frequently faced raids and conflicts. Underground cities offered a powerful form of protection. Entire populations could retreat underground when danger approached.

They might remain hidden for days. Sometimes weeks, possibly even months. When the threat passed, they emerged again and returned to life on the surface.

Living underground for extended periods could not have been easy. There was no sunlight. Lighting came from oil lamps. The tunnels were narrow and often claustrophobic.

But the inhabitants of Derinkuyu designed the city to support daily life. Animals were kept in the upper levels. This helped reduce odors and allowed heat from the livestock to warm the lower chambers.

Food supplies were stored in sealed rooms. Grain, wine, and oil could last for long periods. Some chambers appear to have served as communal gathering areas or classrooms. And deep within the city lies a small church carved directly into the stone.

Even while hiding underground, people continued to worship, learn, and maintain community life. It wasn’t comfortable, but it was survivable. And during times of invasion, survival was the only thing that mattered.

As centuries passed, the need for underground refuge slowly disappeared. Empires stabilized. Trade routes shifted.

Communities rebuilt their lives above ground. The underground city was gradually abandoned. Entrances collapsed. Knowledge of the tunnels faded. Eventually, Derinkuyu disappeared from historical memory.

For hundreds of years, the underground city remained hidden beneath the Earth. Then in 1963, a homeowner trying to stop his chickens from escaping accidentally rediscovered it.

Archaeologists soon arrived and began exploring the tunnels. What they uncovered stunned the world. The discovery revealed one of the largest and most sophisticated underground settlements ever found.

Derinkuyu Is Not the Only Underground City

One of the most surprising things about Derinkuyu is that it isn’t unique. Across the Cappadocia region, researchers have identified more than 200 underground settlements.

Some are small, others are massive. One nearby complex — Kaymaklı Underground City — is another enormous subterranean city. Evidence suggests these underground settlements may even be connected through long tunnels stretching across the region.

If that’s true, then thousands of people could move between cities without ever returning to the surface. In other words: Cappadocia may once have had an entire hidden civilization underground.

Visiting the Underground City Today

Today, Derinkuyu has become one of the most fascinating tourist attractions in Turkey. Visitors descend into the tunnels through narrow passageways carved thousands of years ago.

The air becomes cooler. The ceilings get lower. The tunnels twist deeper into the rock.

Standing inside the chambers, it’s difficult not to imagine the people who once lived here. Families whispering by candlelight. Children learning lessons in stone classrooms. Villagers waiting quietly while armies marched somewhere above their heads.

Above ground, the landscape looks peaceful. Below ground, history still echoes through the tunnels.

Derinkuyu is more than a historical curiosity. It is a monument to human adaptability. When danger threatened their lives, the people of Cappadocia didn’t just build walls.

They built an entire world beneath the Earth. A world where thousands could survive in darkness. A world hidden so well that centuries passed before anyone rediscovered it.

All because one homeowner wondered where his chickens kept going. And decided to knock down a wall.