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.
Via donau
With DoRIS (Danube River Information Services) via donau has participated in the development of a decisive tool for inland waterway transport on the Austrian Danube. In 2006 DoRIS commenced operations and has set the standard for navigation information systems all along the Danube. via donau is working at full speed to develop new and improved services. In addition, via donau supports the implementation of River Information Services in the entire Danube region.