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.
Chain boat navigation
After obtaining a concession to provide chain boat services in 1869, the Danube Steamship Company laid a chain between Vienna and Preßburg (the former name for Bratislava). However, in 1871, some sections of the river were already banning chain shipping. In 1881, chain boats were plying the Danube from Spitz to Linz. There were ten chain ships in use. The chain increasingly broke (on average once per trip) which was the reason why the chain boats were converted in 1890 into tugboats. In 1891, chain boat services were established between Regensburg and Hofkirchen (). In 1896, chain boat services between Vienna and Ybbs ceased and, in 1906, services between Regensburg and Hofkirchen were also terminated.