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.
Economy of Hungary
The major rivers of Hungary are the Danube and the Tisza. The Danube also flows through parts of Germany, Austria, Slovakia, Serbia, and Romania. It is navigable within Hungary for 418 km. The Tisza River is navigable for 444 km in the country. Hungary has three major lakes. Lake Balaton, the largest, is 78 km long and from 3 to 14 km wide, with an area of 592 km. Lake Balaton is Central Europe's largest lake and a prosperous tourist spot and recreation area. Its shallow waters offer summer bathing and during the winter its frozen surface provides facilities for winter sports. Smaller bodies of water include Lake Velence (26 km) in Fejér County and Lake Fertő (82 km within Hungary).