Photo taken on July 31, 2014 shows lake in Guoluo Tibetan Autonomous Prefecture, northwest China's Qinghai Province. Sanjiangyuan, which translates as "source of three rivers," is home to the headwaters of the Yangtze, Yellow and Lancang (Mekong) rivers in northwest China's Qinghai Province. Ecological construction has been going on since 2005. (Xinhua/Wu Gang)