Giant Sinkhole Reveals Enormous Hidden Cave Complex

A sinkhole has revealed an incredible underground cave complex deep beneath the forests of Guangxi, China. The "world-class" structure, which can be seen in the video above, has a volume of 236 million cubic feet.

Earlier this month, a joint China-U.K. team of 19 entered the cave to map its interior. The cave was first discovered last year by a Hong Kong expedition, Zhang Yuanhai of the Chinese Academy of Geological Sciences told China's Science and Technology Daily. "This time we mainly determined its volume and world-class status through three-dimensional scanning," he explained.

The pit of the sinkhole is some 330 feet wide, 650 feet long and up to 390 feet deep, Science Alert reported. At one side, it slumps into the enormous cave structure, with halls, craters, corridors, pillars and smooth, round rocks called cave pearls.

Three-dimensional scans revealed that evidence to explain the crater's collapse still lies in the rocks of the cave hall, Zhang said. "Especially the traces of rock mechanics produced after the collapse, which are clearly visible, demonstrating the evolutionary characteristics of this [large sinkhole]."

Similar sinkholes emerged when underground caverns give way. Water, for example, slowly wears away at the rock, causing it to collapse.

China is home to the largest sinkhole in the world, the Xiaozhai Tiankeng, or Heavenly Pit, which stretches more than 2,000 feet long. Tiankeng is the Chinese word for this kind of massive sinkhole.

"These giant caves are natural caves, most of which are caused by collapses and are related to underground rivers," said Zhang. "The formation of all caves is not a one-step process. They basically have a history of more than 2 million years."

Light travels through a hole in the ground. Getty Images

Although remote sinkholes can be stunning, others have deadly effects on local communities. A sinkhole killed four people in Dazhou city, Sichuan province, when it opened up earlier this month.

In the U.S., 60 sinkholes opened up in Michigan in June after flash floods tore through the state. Heavy rainfall caused chaos in Michigan's Upper Peninsula, with a Houghton police lieutenant telling Newsweek at the time, "We have bridges washed out, roads that have been washed out, homes that have been destroyed…and it's still ongoing."

In May, a sinkhole opened up outside the White House, prompting jokes as well as concern. Jimmy Kimmel even joked it was one of first lady Melania Trump's escape tunnels, adding, "She did ask for a headlamp for Mother's Day."