Features of karst landscapes. (1) phreatic zone; (2) sink hole or doline; (3) polje; (4) vadose region; (5) swallow holes; (6) vauclusian spring; (7) limestone pavement; (8) kamenitza.
Karst is a limestone topography (named after the Karst region of Slovenia), which typically includes irregular protuberant rocks, collapsed caverns, sink holes where streams disappear underground, and areas of bare limestone pavement.
This type of landscape forms where solution weathering wears away much of the limestone, and where rivers erode the rock. Most rivers are underground, and there are caves and large caverns. The largest caverns may collapse to form gorges, and gradually the entire are of limestone may be worn away.