Under the surface of karst forest, there is a wonderful underground world: the karst cave.

Guizhou Province in southwest China is well-known for its karst landforms, of which karst cave is one of the typical ones. 

Cave "Jiudongtian" is one of the incredible caves in Maolan National Nature Reserve (Maolan Karst Forest) in Libo County in Guizhou Province. Its name comes from the fact that there are nine holes in the cave wall through which the sky can be seen. 

The formation of karst caves is the result of long-term groundwater dissolution in the limestone areas. Due to the different amount of limestone in each part of the limestone layer and the different degree of erosion, the caves are gradually dissolved and divided into non-dependent karst caves with stalactites hanging over and stalagmites growing on the ground. 

Due to the lack of light and humid environment, plants can barely seen in caves. However, these holes are like a passageway connecting the green nature outside with the dark and mysterious world inside, creating a breathtaking scenery of the mother nature.

(All photos taken by CGTN's Gao Yuxin)

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