Tourists visit an ice cave in Luyashan scenic area in Ningwu County of Xinzhou City, north China's Shanxi Province, May 4, 2019. According to research, the ice cave with a depth of 100 meters came into being 3 million years ago. [Photo by Cao Jianguo/Xinhua]
Tourists visit an ice cave in Luyashan scenic area in Ningwu County of Xinzhou City, north China's Shanxi Province, May 4, 2019. According to research, the ice cave with a depth of 100 meters came into being 3 million years ago. [Photo by Cao Jianguo/Xinhua]
Tourists visit an ice cave in Luyashan scenic area in Ningwu County of Xinzhou City, north China's Shanxi Province, May 4, 2019. According to research, the ice cave with a depth of 100 meters came into being 3 million years ago. [Photo by Cao Jianguo/Xinhua]