Southwestern China is home to a unique karst landscape dotted with numerous giant sinkholes known as ‘tiankeng.’ These ‘heavenly pits’ are formed by the gradual erosion of limestone bedrock over hundreds of thousands of years, creating enormous pits with steep sides and often harboring pristine ecosystems. Xiaozhai Tiankeng, located in southern-central China, is the deepest sinkhole on Earth, measuring over 100 meters deep. China is home to around 200 tiankeng, with the highest proportion of surface area affected by karst formations globally. Recent discoveries, such as a 630-foot-deep sinkhole in Guangxi, have expanded our understanding of these unique geological features.