Chinese President Xi Jinping inspected the estuary of the Yellow River in the city of Dongying, east China's Shandong Province, on October 20. Established to preserve rare wildlife in October 1992, the Yellow River Delta National Nature Reserve is the largest, youngest and most complete wetland system in China's warm temperate zones. Set at the mouth of the Yellow River, the nature reserve covers an area of around 1,530 square kilometers. Known as the "international airport for birds," more than 6 million birds migrate here every year.