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.
European watershed
Within the Alpine foothills it runs north of the Schussen catchment area of Lake Constance towards the sources of the Brigach and Breg headwaters of the Danube in the Black Forest. It then follows the main ridge of the Swabian and Franconian Jura with the crossing of the Rhine–Main–Danube Canal northeastwards up to the Fichtelgebirge and southeastwards along the Bohemian Forest, forming the border between Germany and the Austrian Mühlviertel and Waldviertel regions with the Czech Republic, where the large Bohemian basin is drained by the Elbe River. It again turns northeastwards along the Bohemian-Moravian Highlands-Javořice Highlands to the Śnieżnik Mountains of the Eastern Sudetes at the border with Poland, where the tripoint of Orlice, Elbe (North Sea) and Morava, Danube (Black Sea) and Eastern Neisse, Oder (Baltic Sea) is located at the peak of Trójmorski Wierch (Klepý, Klappersteine, Three seas peak, 1144 m above sea level).