Gu Shan, situated at the northwestern corner of West Lake, is 38 meters (about 125 feet) above sea-level, and covers an area of 300 mu (nearly 50 acres). It is the lowest summit, compared to other hills around West Lake, but it is also the biggest island in the lake, and the only natural island as well.Gu Shan got this name because it is surrounded by water, standing solitarily in West Lake. It can also be called Solitary Island, for it is a lonely island; rather than a hill. Its other name: Plum Blossom Island, originates from the flourishing plum blossom planted on the hill.