Lu Lin Lake is a firn basin, a place where glacial ice accumulates.  There is a glacial ridge by its side with a hanging valley just below the ridge. Lu Lin Lake was a natural lake with a vast reed grove. 1,700 years ago much of the ridge was washed away. Lu Lin Bridge that you see was built in 1955 on the original glacial spillway. During the Central Committee’s Conference Chairman Mao and other top leaders in China swam in the lake. Today Lu Lin Lake is the main water source for local people.