Forest grows in a giant, 630ft-deep sinkhole

In Leye County, China, a forest grows at the bottom of a humungous sinkhole 630ft-deep. Latest among several such discoveries in the region's spectacular karst landscape, the sinkhole is all but another world—scientists hope to find undiscovered species under its 130-ft canopy.

Live Science:

The sinkhole is 630 feet (192 meters) deep, according to the Xinhua news agency, deep enough to just swallow St. Louis' Gateway Arch. A team of speleologists and spelunkers rappelled into the sinkhole on Friday (May 6), discovering that there are three cave entrances in the chasm, as well as ancient trees 131 feet (40 m) tall, stretching their branches toward the sunlight that filters through the sinkhole entrance. 

Adds international cave expert and executive director of the National Cave and Karst Research Institute George Veni: "This is cool."