Since 1985, UNESCO has recognized the “Rock Sites of Cappadocia” as a World Heritage Site. These are caves that function as living and working spaces, churches and monasteries in the Cappadocia region, Central Turkey.
Since prehistoric times, the Cappadocia region, later recognized as a World Heritage Site, has been covered with a layer of tuff, a type of rock formed from volcanic ash about 20 million years ago. This layer of rock has been eroded by water flows, creating famous rock caves.
Seeing that this type of rock is soft and relatively easy to work, people carved it into tunnels or lodges in the early Bronze Age. Over time, this created living complexes, including monasteries, and eventually became an underground city.

Derinkuyu Underground City
Archaeologists have discovered nearly 40 underground cities in Cappadocia, but only a small portion is accessible to the public, and there may be more yet to be discovered. These cities are connected by long pᴀssageways, and the number of inhabitants in each city varies, ranging from 3,000 to 30,000 people. Özkonak may be the largest, largely unexplored city, with a population of about 60,000, but the most famous are Derinkuyu and Kaymakli.
Derinkuyu is an underground city in Derinkuyu County, Nevşehir Province, with a depth of 85 meters, housing about 20,000 people along with livestock and food stores. This is one of the underground complexes that have been found throughout the Cappadocia region.
These are the houses of the Hitтιтes, or ancient Anatolians. The top of their houses is like the mouth of a well, and the bottom is wide open, with an entrance for livestock, but people go down to the house by ladder. Whole families live in the house with their goats, sheep, cattle and birds.

A basement renovation project led to a lifetime archaeological discovery: the underground city of Derinkuyu, home to 20,000 people

Tunnels in underground cities in Cappadocia open to visitors
The inside of these cities is like a maze, with pᴀssages that can be sealed with large stone doors, about a meter high, with a hole in the center for peeping. In some cities, there are holes in the ceiling, used to attack enemies with spears.
Black Churches Hidden in the Cliffs
This is Karanlık Kilise, a Christian settlement in the Göreme region. In the first centuries after the birth of Jesus, hermits hid in natural caves or dug into the cliffs to create houses. Then, over the years, stone buildings were built above and below ground to form a city. From 642, the Arabs began to invade the area, followed by the Byzantines. By the 11th century, there were about 3,000 churches carved into the rock. The churches were very simple and were rarely or never decorated

Pigeon Valley in Cappadocia
In contrast to the underground cities are the castles in Uçhisar and Ortahisar, on cliffs 60 to 90 meters high, with many entrances to rooms, accommodating about 1,000 people.
Today, the underground cities in the Cappadocia region are a World Heritage Site, attracting millions of visitors every year, bringing huge revenue to Türkiye.