Tourists watch the Hukou Waterfalls on the Yellow River in Linfen, north China's Shanxi Province, July 21, 2016. The Hukou Waterfalls enter a summer flood period due to heavy rainfall in the upstream regions. Photo: Xinhua

Tourists watch the Hukou Waterfalls on the Yellow River in Linfen, north China's Shanxi Province, July 21, 2016. The Hukou Waterfalls enter a summer flood period due to heavy rainfall in the upstream regions. Photo: Xinhua

Tourists watch the Hukou Waterfalls on the Yellow River in Linfen, north China's Shanxi Province, July 21, 2016. The Hukou Waterfalls enter a summer flood period due to heavy rainfall in the upstream regions. Photo: Xinhua

Tourists watch the Hukou Waterfalls on the Yellow River in Linfen, north China's Shanxi Province, July 21, 2016. The Hukou Waterfalls enter a summer flood period due to heavy rainfall in the upstream regions. Photo: Xinhua