How do sinkholes form in limestone regions?

In karst landscapes, rainwater picks up carbon dioxide from the air and soil, forming weak carbonic acid. That water can dissolve limestone, gypsum, or other soluble rocks over long periods, enlarging fractures and cavities underground. If the cavity grows large enough, the overlying ground may sag gradually or collapse suddenly, producing a sinkhole. Sinkholes are common in regions with abundant limestone and active groundwater flow, such as Florida, parts of China, and the Yucatán Peninsula. Human activities like groundwater pumping can sometimes speed up collapse.