These rocks are a popular photography site for tourists visiting Mount Siguniang in Sichuan Province. /CGTN

No, it's not rust! It's actually a kind of red moss growing on the boulders in the riverbeds of Mount Siguniang in southwest China's Sichuan Province.

Editor Ⅰ: Zhang Wenwen

Editor Ⅱ: Wu Dan

Editor Ⅲ: Liu Guosong