What are the best in China today or in history?

Wannian Ice Cave in Ningwu, Xinzhou is the largest ice cave in China. Wannian Ice Cave is located in the east of Madigou Village, Qianshan Township, ningwu county. It was formed in the Cenozoic Quaternary Glacier Period and has a history of 3 million years. It is unique in that, based on the climatic conditions outside the local cave, it is impossible to form an icy environment. The icicles in the cave do not melt all the year round, and the deeper the ice, the thicker it becomes. It is the largest ice cave found in China so far, and it is also a rare large ice cave found outside the frozen soil in the world so far.