Tower karst is a spectacular variety of karst landscape dominated by steep or vertical sided limestone towers. Towers originate as residual cones and are then steepened by water table undercutting from surround alluviated plains. Tectonic uplift matched by karst erosion then increases tower heights, but if uplift exceeds surface lowering the towers are raised to hillside locations and the landscape is rejuvenated to form a new generation of dolines and cone karst. Many towers are riddled with relict caves at high levels, and with active caves through their bases, [but] unlike their counterparts in the temperate mid-latitudes, caves in the tropical karst regions are shallow and not well developed. They usually consist of a network of small tunnels rather than an extensive system of caverns.
Towers that characterize tower karst can only develop in the tropics because it is only there that the right conditions of rock and climate — development requires a minimum of 120 cm of precipitation per year and an average temperature of 18 °C — interact to create these magnificent features.
- Cockpit karst is the beginning of the development. After cave systems developed, grew and collapsed, the former caves form huge valleys and the limestone in between remains as hills.
- Cone karst is the more common and less spectacular form of this landscapes with limestone hills, residual cones, typically covered by rain forest.
- Tower karst is the spectacular form with 30-300m high towers with vertical or overhanging sides. The walls are typically bare rock, as the walls are too steep for vegetation.
Tower karst occurs throughout southeast Asia. By far the most extensive and best developed tower karst is in the Guangxi province of southern China. This is the ultimate development of tower karst, in which the residual hills have very steep to overhanging slopes. Other famous areas of tower karst are Vietnam, Thailand and Malaysia. Cone karst occurs in Cuba, Madagaskar and Puerto Rico. Very common is submerged tower karst on the coast of Thailand and in the Chinese Sea. The towers form steep limestone islands in the sea, sometimes with donlines inside that form salt water lakes with steep walls.