Crystal ice drifts in Heihe River (1/6)

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)

Known as the "mother river of the Hexi Corridor", Heihe River is the second largest inland river in China with a total length of 928 kilometers, extending the provinces of Qinghai, Gansu and Inner Mongolia Autonomous Region.

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)

Crystal ice floats in the upper stream of Heihe River in Qilian County, Haibei Tibetan autonomous prefecture, northwest China's Qinghai Province. (Photo: China News Service/Bao Lei)