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.
Transport in Serbia
There are 1,716 kilometers of navigable inland waterways (1,043 km of navigable rivers and 673 km of navigable canals), which are almost all located in northern third of the country. The most important inland waterway is the Danube (part of Pan-European Corridor VII). Other navigable rivers include Sava, Tisza, Begej and Timiş River, all of which connect Serbia with Northern and Western Europe through the Rhine–Main–Danube Canal and North Sea route, to Eastern Europe via the Tisza, Begej and Danube Black Sea routes, and to Southern Europe via the Sava river. The largest river port is Novi Sad (1.18 million tons of cargo tonnage in 2016), while other river ports include Belgrade, Smederevo, Pančevo, Prahovo, Apatin, Bačka Palanka (all on Danube), Šabac (on Sava), and Senta (on Tisza).