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.
Budapest
The river Danube flows through Budapest on its way from Germany to the Black Sea. The river is easily navigable and so Budapest historically has a major commercial port at Csepel District and at New Pest District also. The Pest side is also a famous port place with international shipping ports for cargo and for passenger ships. In the summer months, a scheduled hydrofoil service operates on the Danube connecting the city to Vienna.