This underground settlement is located on the hill named "citadel" in the village of Tatlarin, 10 km north of Acigol, in the province of Nevsehir. The underground settlement was first discovered in 1975 and in 1991 it was opened up for visitors. Apart from the underground settlement, there are a lot of churches near the citadel; however, most of them have collapsed due to natural causes. Although the original entrance of the underground settlement has collapsed, two places in the west remain to provide access to the underground settlement. The underground settlement covers a large area; however, only a small part of it has been opened. Two floors are open to visitors.

The size of the spaces, the number of the storage rooms and the great number of churches indicate that this place was either a garrison or a monastery complex rather than an underground settlement. A 15 m long , curving corridor leads from the entrance to a large rectangular area. At the entrance, to control access to the underground settlement there is a millstone door which has a hole in the center and is 1.5 m in diameter. In a place, hollowed out inside the niches on the right and called a "dungeon" by the local people, three skeletons were found.

To the right of this main place, where the toilets are also found, there is a cellar/kitchen. This place must have been used as a graveyard in the Roman Era, and as a cellar in the Byzantine Period because the niches in this room are the same as the niches where the dead were laid in the tombs belonging to the Roman Era in this area. However, later the floors of these niches were hollowed out and provisions were kept in these places.

The stable is at the second entrance. This large area, which is supported by columns, was definitely used as a storage room before. There are five storage rooms on the floor of this area. On the ceiling there is a ventilation shaft reaching the other spaces in the underground settlement. The first and the second large areas are connected with a narrow passage. In this zig-zag shaped corridor, there is a millstone door to close the entrance and a trap as well.