A vast sinkhole complete with a “well-preserved primitive forest” at the bottom has been discovered in the remote forests of south China's Guangxi Zhuang Autonomous Region.
A team from the Institute of Karst Geology of China Geological Survey recently discovered the karst sinkhole in Leye County, measuring in at 306 meters (1,0003 feet) in length, 150 meters (492 feet) in width, and 192 meters (629 feet) in depth, according to Chinese news agency Xinhua.
Satellite images initially hinted that a sinkhole might be lurking within this densely forested pocket of China. To confirm its existence, researchers trekked deep into Guangxi Zhuang Autonomous Region to see the geological feature with their own eyes.
The expedition team abseiled down more than 100 meters (328 feet) and hiked for several hours to reach the base of the sinkhole. Here, they discovered dense overgrowth as a high as person’s shoulders with “ancient trees” growing up to 40 meters (131 feet) tall.
"I wouldn't be surprised to know that there are species found in these caves that have never been reported or described by science until now," commented Chen Lixin, who led the cave expedition team, according to Live Science.
A video of the sinkhole can be seen below.
Giant sinkholes are known as tiankeng in China, which roughly translates to “heavenly pit.” These deep underground caverns are formed by slightly acidic rainwater draining through the earth and slowly eroding the soluble bedrock. With enough time, winding underground tunnels and caverns can form beneath the ground. A sinkhole occurs when the top “ceiling” becomes so thin and weak it caves in to expose the underground cavity.
Due to its karst geology, this part of China is no stranger to sinkholes. Leye County alone is home to at least 29 other similar sinkholes and is sometimes referred to as the "tiankeng capital of the world."