Blautopf

Blautopf with the bright limestone sediments underwater
Blautopf with hammer mill

The Blautopf (German for Blue pot) is a spring that is considered the source of the river Blau in the karst landscape on the Swabian Jura's southern edge. It is located in Blaubeuren, Alb-Donau-Kreis, Baden-Württemberg, Germany (approximately 16 km (9.9 mi) west of Ulm).