This three million year old ice cave is one of China's natural wonders

​Photo shows the Ice Cave in Ningwu County in Shanxi Province on August 13, 2018. Found by the Institute of Geology and Geophysics of the Chinese Academy of Sciences, it is said to have been formed during the fourth glacial period around three million years ago. The cave, which is at an altitude of 2,300 meters, became a National Geological Park in 2005. [Photo: IC]