Introduction to Siyan Cave: Siyan Cave is about 30 meters south of Erlianhua North Cave. It is a medium-sized cave in the prosperous Tang Dynasty. The roof of the cave is a lotus caisson. The lotus caisson is surrounded by four flying geese. The strange thing is that the legs of these four geese are very slender, similar to the legs of a crane. This is where the name of the Four Wild Geese Cave comes from. Here it is.