Hainan Tibetan Autonomous Prefecture of Qinghai Lake in Qinghai, the total area of 18 square kilometers of the island is the largest island in the lake, about 13 kilometers, set a maximum width conventional 2. 8 kilometers, 58 meters above the lake, rather like a crescent type of large sand dunes, is the lake surface ridges prominent role by the sand deposited by for the lake one of the major spectacle.