630-foot-deep giant sinkhole with forest at the bottom discovered in China

A 630-foot-deep giant sinkhole with a forest at the bottom has been discovered in China's Leye County, the Xinhua news agency reported. Zhang Yuanhai, senior engineer at the Institute of Karst Geology of China Geological Survey, said that there are three caves within the sinkhole. "This is cool news," said an official from US' National Cave and Karst Research Institute.