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.
The Ister (film)
Eventually the film arrives at Donaueschingen, and at the Breg and the Brigach, the two tributaries whose confluence marks the point at which the river becomes known as the Danube. The film then travels upstream along the Breg, past Vöhrenbach and Furtwangen, in search of the "true" mountain source of the Danube.