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.
Danube
The Sultans Trail is a hiking trail that runs along the river between Vienna and Smederevo in Serbia. From there the Sultans Trail leaves the Danube, terminating in Istanbul. Sections along the river are as follows.