Tourists watch the Hukou Waterfall in Jixian County in north China's Shanxi Province, Feb. 21, 2018. As temperature rose in recent days, water of the Yellow River at the Hukou Waterfall melted, which attracted many tourists. (Xinhua/Lyu Guiming)

Tourists watch the Hukou Waterfall in Jixian County in north China's Shanxi Province, Feb. 21, 2018. As temperature rose in recent days, water of the Yellow River at the Hukou Waterfall melted, which attracted many tourists. (Xinhua/Lyu Guiming)