Yongding River, historically the biggest to flow through Beijing, is known as the mother river of the capital city. The river flows through Inner Mongolia, Shanxi, Hebei, Beijing and Tianjin. Spanning 170 kilometers within the capital city, it runs through five districts in the west and south, including Mentougou, Shijingshan, Fengtai, Fangshan and Daxing. The municipal government launched a five-year-long project in 2010 to restore the river’s ecological system, which is expected to be an ecological corridor covering an area of 1,500 square meters in 2014. [Chinaa.org.cn/Photo by Dong Nianlong]