An international expedition has discovered more than 20 caves and sinkholes with great research value in South China's Guangxi Zhuang autonomous region, China Central Television (CCTV) reported on March 26.

A Chinese explorer walks across one of the "halls" found in the one-kilometer-long karst cave network. [Photo by Wei Ludong/Hechi Daily]

The 25-member team consisting of explorers and reporters from China, France and Italy investigated 21 caves near the Donglan county over four days, and managed to unravel some mysteries inside.

A Chinese explorer examines bead-shaped rocks found on the cave floor. [Photo by Wei Ludong/ Hechi Daily]

One of the most exhilarating findings is the Ganfan Cave near the Yangyou village in Mulan town. The one-kilometer underground karst cave has eight "halls" filled with cave pearls, stalactites and stalagmites of various shapes and sizes, and is believed to be the largest cave found in the area so far.

With the help of drones, explorers also discovered a gigantic sinkhole – the Ganyan Tiankeng (literally meaning "heavenly pit") – tucked away in thick forest by the Hongshui River. Steam can be seen rising from the bottom of the 350m-deep, 150m-wide sinkhole.

The karst caves are filled with strange rock formations, shaped by changes over time. [Photo by Wei Ludong/Hechi Daily]

It's first cave exploration in Donglan for the expedition team since March last year.

Local authorities said the findings will contribute to the county's construction of an international geographical park in the future.

Stalactites shaped like the wings of dragons hang from the cave's ceiling. [Photo by Wei Ludong/Hechi Daily]

Sitting on the Donglan-Bama-Fengshan triangle, Donglan is known for the longevity of its residents, which can be partly attributed to its 77 percent forest coverage and pristine natural environment.

Ganyan Tiankeng is a 350m-deep, 150m-wide sinkhole tucked away in thick forest by the Hongshui River. [Photo by Huang Shangbiao/Hechi Daily]