A rainbow stretches over the frozen Hukou Waterfall on the Yellow River, at the intersection of Shanxi and Shaanxi provinces on Dec 27. As the second-largest waterfall in China, Hukou Waterfall, which is some 50 meters high and 30 meters wide, sees a great number of visitors each year. [Photo by Lyu Guiming/China Daily]

A rainbow stretches over the frozen Hukou Waterfall on the Yellow River, at the intersection of Shanxi and Shaanxi provinces on Dec 27. As the second-largest waterfall in China, Hukou Waterfall, which is some 50 meters high and 30 meters wide, sees a great number of visitors each year. [Photo by Lyu Guiming/China Daily]