Subscribe to our newsletter. The underground water of karst topography carves our impressive channels and caves that are susceptible to collapse from the surface. Sinkholes are depressions that form when a portion of the lithosphere below is eroded away.
Sinkholes are common in Florida where they're often caused by the loss of groundwater from pumping.
A sinkhole can even collapse through the roof of an underground cavern and form what's known as a collapse sinkhole, which can become a portal into a deep underground cavern. While there are caverns located around the world, not all have been explored. Many still elude spelunkers as there is no opening to the cave from the earth's surface. Inside karst caves, one might find a wide range of speleothems - structures created by the deposition of slowly dripping calcium carbonate solutions. When stalactites and stalagmites meet, they forum cohesive columns of rock.