Danube
Classified as an international waterway, it originates in the town of Donaueschingen, in the Black Forest of Germany, at the confluence of the rivers Brigach and Breg. The Danube then flows southeast for about , passing through four capital cities (Vienna, Bratislava, Budapest and Belgrade) before emptying into the Black Sea via the Danube Delta in Romania and Ukraine.
Breg (river)
The " Breg " is the longest and biggest headstream of the River Danube. It flows through the southeast part of the Middle Black Forest and the lowlands of the Baar region.