Introduction to Erxian Cave: Erxian Cave is located on the west side of Shuanglong Cave, also known as Shuanglong Castle. The cave has three floors, including two underground rivers, five corridors, five halls, stone flowers, stalagmites, Stone stalactites, stone curtains, waterfalls, grand canyons, etc. are rare in China. There are 13 mysterious patterns of "Stone Book of Heaven" engraved on the cave wall.