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.
Yantra (river)
The Yantra () is a river in northern Bulgaria, a right tributary of the Danube. It is long (the second longest Bulgarian tributary of the Danube, after Iskar) and has a watershed of .
The Yantra has its source from the northern foot of Hadzhi Dimitar Peak in Central Stara Planina, at . In its upper course, it is often called "Etar" (Етър), its older name. The river flows into the Danube close to Svishtov.