A tourist takes a photo inside the ice cave. [Photo/IC]

Located 50 kilometers west of Ningwu county in north China's Shanxi province, the ice cave in Luyashan Mountain was formed in the glacial epoch in the quaternary period about 3 million years ago.

At more than 100 meters in depth, it is the biggest ice cave ever discovered in China.

The climate condition outside the cave doesn't facilitate the form of ice. During the summer season, temperatures can roar to 40 degrees centigrade. However, the ice pillars inside the cave never thaw as the inside temperature stays at a cool minus 4 degrees centigrade throughout the year.