Deep in the misty valleys of China's Guangxi Zhuang Autonomous Region, a gaping sinkhole leads the way to a vast "world-class" cave hall.
The giant cave hall was explored for just the second time by a China-UK joint expedition earlier this month. As reported by BBC News, the team lowered themselves into the newly discovered cave hall using a single 200-meter (656-foot) rope and began to explore the 6.7-million-cubic-meter (236-million-cubic-foot) cavern.
Footage from Chinese television (below) shows the surprisingly beautiful interior of the cave, complete with clear blue waters, collapsed rock, and other geological features.
"This giant cave hall was actually discovered by the Hong Kong expedition last year, so it was named Hong Kong Haiting Hall. This time we determined its volume and world-class status through three-dimensional scanning," Zhang Yuanhai, a researcher at the Institute of Karst Geology of the Chinese Academy of Geological Sciences, told the Chinese media outlet Science and Technology Daily.
The causes of sinkholes vary from case to case, but they are often triggered by circulating groundwater slowly dissolving away limestone rock, salt beds, soils, or other soluble rocks, such as gypsum. Eventually, when enough erosion has occurred, the floor can give way, exposing underground cave networks.
This corner of rural China is no stranger to sinkholes. North of Guangxi, Chongqing Municipality in south China is home to Xiaozhai Tiankeng, also known as the Heavenly Pit, which is believed to be the world’s deepest sinkhole.