A mysterious and rare scene shows clouds flowing through a mountain passage in southern China's Tianmen National Park after rainfall.<br /><br />In the video, shot in Zhangjiajie City in Hunan Province on April 20, the clouds can be seen flowing down into a 131.5-metre-high, 57-metre-wide and 60-metre-deep Tianmen Cave, which is a natural karst cave through mountains.
