Introduction to Shuanggui Suoguan: Wangquanyuguan is located at the bottom of the mountain pass and is also called "Longmen Shuiguan" by the locals. In 1972, a flash flood broke out and the Shuiguan was destroyed by trees and rocks. There is a natural wonder "Double Turtle Lock Pass" in Wangquanyuguan. There is a huge natural rock on the mountainside on the east and west sides of the pass, shaped like a turtle, carrying the Great Wall on its back.