In 112070944291963, a resident of Cappadocia, Turkey discovered a mysterious room behind the wall of his house, marking the beginning of the rediscovery of the ancient underground city of Derinkuyu. This city was primarily built by the Phrygian people, who were master architects of the Iron Age, and they accomplished this great feat between the 12th and 7th centuries BC. This vast city remained hidden beneath the surface of the earth for centuries. Over time, various civilizations, particularly the Byzantine Empire, expanded it.

Derinkuyu, one of the largest cities of its kind, could shelter thousands of people and livestock. It is a magnificent example of ancient engineering and human ingenuity.

Additional interesting information:

- This city consists of eight floors and is approximately 85 meters (280 feet) deep underground.

- The city had over 600 secret entrances that could be blocked by large stones.

- There were churches, schools, storage rooms, wineries, and water wells present.

- The city featured a complex ventilation system that ensured the supply of fresh air through 15,000 small shafts.

- This city was specifically built to protect against enemy attacks and could easily shelter up to 20,000 individuals.