Introduction to Yanzi Cave: Yanzi Cave Scenic Area, with an altitude of 1,200 meters and a cave length of about 4 kilometers, is one of the most spectacular and largest cave groups in Asia. . It got its name because there are millions of swifts nesting on the rock walls inside and outside the cave, and the cave is rich in bird's nests. It is located in Jianshui County, Honghe Hani and Yi Autonomous Prefecture.