Birds fly over Shanghai Chongming Dongtan National Nature Reserve in Chongming District, east China's Shanghai, Dec. 20, 2017. Located in the middle of east China's coast line and the estuary of the Yangtze River, Shanghai is China's largest economic center as well as the regional hub of Yangtze River Delta region. As the backyard of this prosperous metropolitan, Chongming Island, one of Shanghai's rural districts, is on its way to achieve its goal to develop a world-class ecological island. The island's wetlands are preserved, and its traditional villages are renovated. Green and organic agriculture and eco-friendly industries have developed into local economic pillars. Chongming is endeavored to become a model of ecological preservation development among cities in the Yangtze River Delta and Yangtze River Economic Belt. The Beijing International Horticultural Exhibition kicked off its "Shanghai Day" event from last Sunday to Monday. (Xinhua/Fang Zhe)