A river never freezes in Hinggan League of North China's Inner Mongolia autonomous region, although the air temperature reaches as low as minus 30 degrees Celsius.

The river, located 74 kilometers away from the downtown area of Hinggan League's Arxan city and stretching for 20 kilometers, is called the Unfrozen River by the locals.

This is due to volcanic activity underground which produces an abundance of geothermal energy –– keeping the water temperature above freezing. At times, steam is also visible, rising from the flowing water.