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.
Executive Agency for Exploration and Maintenance of the Danube River
The Agency works in cooperation with the inland waterway administrations in the other states along the Danube River. It takes part in workshops in the field of navigation and inland waterway maintenance and implements projects in the frames of the Danube Strategy of the EU, Bulgarian-Romanian commissions, the Danube Commission, GIS Forum.