The Dailincouyou underground city has the largest number of rooms. It has more than 1200 rooms, about 18-20 floors. Each floor has vents. At present, it is only open to the outside world to the 8th floor. The dungeon was built because men fought on the ground and women, children and the elderly lived in the dungeon in order to avoid persecution by the Arabs. Its name is Dungeon, because it's really a city! Rooms, chapels, schools, breweries, warehouses and other facilities are all available, and even cemeteries. At most, 40,000 people live.