Karst spring

A 130-metre (430 ft) deep karst spring of the Cetina River in Croatia
Buna Wellspring
The Vrelo Bune (English: Wellspring of the Buna) with the Blagaj Tekke under a limestone cliff in Bosnia
Blautopf (Blue Pot), karst spring of the River Blau (River Blue) in Blaubeuren, Swabian Jura

A karst spring or karstic spring is a spring (exsurgence, outflow of groundwater) that is part of a karst hydrological system.