Kilometer-square Area Radio Synthesis Telescope (KARST) is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors built on bowl-shaped limestone sinkholes, in a karst landform in China. It will consist of about 30 individual elements, each about 200 meters in diameter. A site survey of 288 suitable locations was performed in Pingtang county, Guizhou province, and optimal sites will be chosen with an eye towards signal performance.

Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes, dolines, and caves. It has also been documented for weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water with few to no rivers or lakes. However, in regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst surface developments might be totally missing.