Several whooper swans fly over the Qinghai Lake in Xining, capital of northwest China's Qinghai Province, Dec. 13, 2012. With investment and protection from State Government and Qinghai government, the level of Qinghai lake continues to rise and the area of the lake has been increasing year after year. Qinghai Lake covered an area of 4,317 square kilometers in 2008, which increased 4,354 square kilometers in 2012. The growth equals 6 times the area of West Lake, a famous lake in east China's Zhejiang Province. [Xinhua/Zhang Hongxiang]