Karst

geology · caves · limestone

Water dissolves rock. Karst forms when rainwater seeps into soluble rocks like limestone and dolomite, slowly dissolving them from the inside out. Over thousands of years, this creates huge caves and tunnels underground.

Sinkholes appear suddenly. When the rock underneath gets thin enough, the ground above suddenly collapses, creating a sinkhole. These can be small or large enough to swallow buildings.

Underground rivers flow. Instead of flowing on the surface, water in karst regions runs through hidden cave systems underground. These underground rivers eventually empty into springs that burst out of the ground.

Unique landscape features. Karst areas often have rolling hills with lots of valleys called poljes, and barely any streams or rivers above ground because the water is traveling beneath your feet.

Other rocks too. While limestone and dolomite form most karst, even hard rocks like quartzite can create karst landscapes under the right conditions.