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.
Source of the Danube
There was an active rivalry between the municipalities of Furtwangen and Donaueschingen for the claim of being home to the "official" source of the Danube since the 1950s, sometimes with the involvement of the government of the state of Baden-Württemberg. 
Thus, in 1981 the state government granted Donaueschingen the request that the source in Furtwangen should no longer be labelled "Donauquelle" in official maps.