Caves, caverns, sinkholes, dolines and karst landscapes produced by the dissolution of soluble rock, chiefly limestone and dolomite, by acidic water, following the karst landform class of standard geomorphology. Includes cave systems (Waitomo Caves, Krubera Cave, Marble Caves), sinkholes and collapse dolines, and karst tower and pinnacle landscapes where dissolution leaves isolated limestone hills and forests standing (Tsingy de Bemaraha, Shilin Stone Forest, Li River Karst, Chocolate Hills). Belongs here: any formation whose defining shape comes from the dissolution of soluble rock. Does not belong here: a water-filled vertical karst shaft with its own strong regional identity and naming convention (Cenotes), or a formation shaped by mechanical erosion with no dissolution involved (Gorges and Canyons, Other Erosional Landforms).