China's 'heavenly pits': The giant sinkholes that have ancient forests growing within

This giant karst sinkhole, also called a tiankeng, has plants growing at the bottom in Luoquanyan Village of Xuan'en County, central China's Hubei Province. This is not the sinkhole discovered in Guangxi Zhuang Autonomous Region.

QUICK FACTS

Name: Tiankeng, or "heavenly pits"

Location: Guizhou, Guangxi, Yunnan and Chongqing in southwestern China

Coordinates: 24.853407656078527, 106.74287500000897

Why it's incredible: China's enormous sinkholes make the landscape look like someone has taken a hole punch to it. 

Take one look at the giant sinkholes that pockmark China's southwestern regions and it's easy to see why they are dubbed "tiankeng" — a Mandarin word meaning "heavenly pits." Not only do the sinkholes look like they were punched out of the landscape with a cookie cutter, they also harbor primitive forests and pristine ecosystems, according to the UNESCO Courier.