In 1963, a man, living in Turkey, decided to do some renovations on his home. When he knocked down a wall, he found a strange room on the other side, connected with a hallway with a tunnel-shaped look. Little did he know at that time that he had just come across a massive Derinkuyu underground city.
When studied, it appeared to be thousands of years old. It had underground water sources that could not be messed with by any surface dwellers. It had shops, homes, and even a school. Amazingly, they also kept livestock down there.
The town appeared to hold 20,000 people! It gets even more interesting. It appears that the town was connected to other underground towns and might have originally been built by the Persians.
Between a few levels, there is a vertical staircase that leads to a church. The town had vent holes. Access points to the outside had stone doors with a hole in the center to peer out and see who was coming.
Today, tours are allowed in about half of the town.
So, what drove these people below in such a massive project? They remain rather vague about why they think this unbelievable undertaking was done, stating it might have been an escape route for raids. It was believed to be used as recently as the 5th to 10th century AD.
We are left with an interesting puzzle of who built this massive structure and why the needed it. As usually, archaeologists are remaining rather vague about the concepts, but hopefully some day something above ground reveals who the tormenting forces were and why an entire city needed to go underground.