17.The Wulong Karst

Are you walkin’ on sunshine? For those with a fear of heights, you might be sweating just looking at this death-defying act. The image on the right is from 2016, during a high-wire walking competition over the 300-meter-high Wulong karst in Chongqing, China. A “karst” is a topographical region formed from the dissolution of soluble rocks. This particular karst contains the Qingkou Tiankeng, a large sinkhole, but not far from the Wulong karst in Chongqing is the Xiaozhai Tiankeng (pictured left), the world’s deepest sinkhole. Tiankeng translates to “Heavenly pit.”

While the next sinkholes aren’t known for being nearly as deep, the water that resides in them often changes color.