Colorful lights make Ningwu ice cave in Shanxi province a beautiful fairyland for tourists. The cave is located at an altitude of 2,300 meters and formed around 3 million years ago. People are most amazed by the fact the cave remains frozen even when temperatures outside the rise into double digits. [Photo/people.com.cn]

Translucent icicles in the cave hold the wonderful colors set off by lights. The ice cave, a national geological park, came into being during the ice age, around 3 million years ago, according to the field work of experts from Chinese Academy of Sciences. [Photo/people.com.cn]