Danube
The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in the world. Ordered from the source to the mouth they are:
The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Württemberg, Germany. About 60 of its tributaries are also navigable.
Elbe
The Elbe has been navigable by commercial vessels since 1842, and provides important trade links as far inland as Prague. The river is linked by canals (Elbe Lateral Canal, Elbe-Havel Canal, Mittellandkanal) to the industrial areas of Germany and to Berlin. The Elbe-Lübeck Canal links the Elbe to the Baltic Sea, as does the Kiel Canal, whose western entrance is near the mouth of the Elbe. The Elbe-Weser Shipping Channel connects the Elbe with the Weser.