Giant sinkhole found in China has hidden forest with ancient trees growing at its floor

Cave explorers in southern China may have found the modern-day equivalent of The Lost World.

At the bottom of the newly discovered 630-foot deep sinkhole lies a hidden forest, lush with shoulder-high flora and tall trees.

Researchers also think there may be new species of animals and plants within the sinkhole, which is made up of three caves and measures 5 million cubic meters, the equivalent of 2,000 Olympic swimming pools.

The sinkhole was discovered in the Guangxi Zhuang Autonomous Region, near Ping'e village in the county of Leye, according to the Chinese government's official news agency Xinhua, The area of southern China is known for its caves, sinkholes, and karst forests, limestone formations that populate the landscape.

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Leader of the cave exploration team, Chen Lixin, told Xinhua the ancient trees growing at the bottom of the sinkhole are nearly 130 feet tall – taller than most oak trees. Dense shade plants grew as tall as the explorers' shoulders, Lixin said.

"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," Lixin said, according to Live Science.

These type of sinkholes and caves could harbor new flora and fauna, international cave expert George Veni told Live Science. "This is cool news," said Veni, who was not involved in the discovery or exploration of this new cave. He is the executive director of the National Cave and Karst Research Institute in Carlsbad, New Mexico.

Sinkholes and caves are created over time as water dissolves limestone, according to the institute. Large sinkholes can have small ponds and fields of plants at the bottom.

Zhang Yuanhai, a senior engineer with the Institute of Karst Geology of China Geological Survey, categorized the find as a large sinkhole, with a well-preserved primitive forest at the bottom, Xinhua reported.

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The explorers completed their expedition on May 6, emerging from the sinkhole after rappelling more than 100 meters down (about 330 feet) and walking several hours to reach its bottom, according to Xinhua. The sinkhole measures about 1,000 feet in length, 500 feet in width and 630 feet in depth.

That such a sinkhole might be found in China is not a big surprise because the region has "this incredibly visually spectacular karst with enormous sinkholes and giant cave entrances and so forth," Veni told Live Science.

Zhang Yuanhai was part of a team that explored an even larger sinkhole found in Guangxi five years ago.

This latest discovery brings the region's number of such sinkholes to 30, Xinhua reported. Mexico and Papua New Guinea are other countries where sinkholes are frequently found.

Follow Mike Snider on Twitter: @mikesnider.

This article originally appeared on USA TODAY: China sinkhole found with ancient forest, tall plants at the bottom