A stalactite shaped like a kind of Chinese stringed instrument pipa. [Photo by Liu Wei/chinadaily.com.cn]

Reasons behind the natural wonder are reportedly the crustal movement of Yanshan mountain and Himalayas.

Some form mirror images of each other. It's said that water dropping from the ceiling adds a fifth of a millimeter to the stalagmites' tips a year. The sands of time have fused some into hourglass-shaped pillars.

Their surfaces undulated with the accumulations of sedimentary minerals collected over hundreds of millennia.

On Sep 19, 2015, Zhijindong Cave National Geopark was approved by UNESCO as a world geopark, becoming the first world geopark in Guizhou province.