Photo taken on Nov. 20, 2019 shows an unfrozen section of the Halha River in the city of Arxan of Hinggan League, north China's Inner Mongolia Autonomous Region. Despite Arxan's frigid winter cold, this geothermally-affected, 20-kilometer section of the Halha River never freezes even when the temperature drops to as low as minus 40 degrees Celsius. (Xinhua/Peng Yuan)