Shengtian Lake is a wetland national nature reserve in Yuncheng City, north China's Shanxi Province. As its ecological system has improved, thousands of swans migrate from Mongolia to the wetland to spend winter every year. These swans sometimes straighten their necks and sing, and sometimes spread their wings and fly, creating a harmonious scenery of Shengtian Lake. Join CGTN to admire the beauty of the migratory swans closely.