Tsingy De Bemaraha, Melaky Region, Madagascar

Due to subterranean drainage, there may be very limited surface water, even to the absence of all rivers and lakes. Many karst regions display distinctive surface features, with sinkholes or dolines being the most common. However, distinctive karst surface features may be completely absent where the soluble rock is mantled, such as by glacial debris, or confined by a superimposed non-soluble rock strata. Some karst regions include thousands of caves, even though evidence of caves that are big enough for human exploration is not a required characteristic of karst.
Various karst landforms have been found on all continents except Antarctica.
Karst topography is characterized by subterranean limestone caverns, carved by groundwater.The geographer Jovan Cvijić (1865–1927) was born in western Serbia and studied widely in the Dinaric Kras region. His publication of Das Karstphänomen (1893) established that rock dissolution was the key process and that it created most types of dolines, "the diagnostic karst landforms". The Dinaric Kras thus became the type area for dissolutional landforms and aquifers; the regional name kras, Germanicised as "karst", is now applied to modern and paleo-dissolutional phenomena worldwide. Cvijić related the complex behaviour of karstic aquifers to development of solutional conduit networks and linked it to a cycle of landform evolution. After Cvijić, two main kinds of karstic areas exist: holokarst i.e. karst developed at whole as it is Dinaric region along eastern Adriatic coast comprises deep in the inland of Balkan Peninsula and merokarst developed imperfectly with some karstic forms as it is in eastern Serbia. He is recognized as "the father of karst geomorphology".