The Danube flows through or along the borders of 10 countries, more than any other river in the world.
It rises in Germany's Black Forest and travels about 2,850 kilometers before reaching the Black Sea. Along its course it passes through or borders Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine. Four national capitals—Vienna, Bratislava, Budapest and Belgrade—stand directly on the river.
The Danube has long connected central and southeastern Europe for trade, transport and cultural exchange. Its delta, shared mainly by Romania and Ukraine, is one of Europe's largest wetlands and reaches the Black Sea.
The Volga is Europe's longest river, but it flows entirely within Russia. The Danube's distinction concerns the number of countries linked by its course, not its total length.