Visitors view the Hukou Waterfall of the Yellow River, which is located on the border area between North China’s Shanxi and Northwest China’s Shaanxi provinces, May 15, 2017. [Photo/Xinhua]

Visitors view the Hukou Waterfall of the Yellow River, which is located on the border area between North China’s Shanxi and Northwest China’s Shaanxi provinces, May 15, 2017.[Photo/Xinhua]

Visitors view the Hukou Waterfall of the Yellow River, which is located on the border area between North China’s Shanxi and Northwest China’s Shaanxi provinces, May 15, 2017.[Photo/Xinhua]