Cappadochia - Up to 36 underground cities have been discovered so far, of which Kaimakle is the largest. The first was the dungeon built by the Hittites, and then Christians fled the Roman massacre into the dungeon, and increased the size of the building. The whole dungeon was 40 meters deep, with a total of eight floors. It was said that it could accommodate 10,000 people at that time. Like the subterranean and narrow maze of urban and rural areas, there are many traces of past life and various living facilities are very complete, which shows the wisdom and wisdom of the ancients.