List of tributaries of the Danube
The Danube is Europe's second-longest river. It starts in the Black Forest in Germany as two smaller rivers—the Brigach and the Breg—which join at Donaueschingen, and it is from here that it is known as the Danube, flowing generally eastwards for a distance of some , passing through several Central and Eastern European capitals, before emptying into the Black Sea via the Danube Delta in Romania.
Sava
The Sava (; , , ) is a river in Central and Southeastern Europe, a right tributary of the Danube. It flows through Slovenia, Croatia, along the northern border of Bosnia and Herzegovina, and through Serbia, discharging into the Danube in Belgrade. Its central part is a natural border of Bosnia-Herzegovina and Croatia. The Sava forms the northern border of the Balkan Peninsula, and the southern edge of the Pannonian Plain.