The Danube is a river in Central Europe, the continent's second longest after the Volga.
The Danube originates in the town of Donaueschingen which is in the Black Forest of Germany. Then it flows southeast for 2 872 kilometers, passing through four Central European capitals before emptying into the Black Sea via the Danube Delta in Romania and Ukraine.
Once a long-standing frontier of the Roman Empire, the river passes through or touches the borders of ten countries: Romania, Hungary, Serbia, Austria, Germany, Slovakia, Bulgaria, Croatia, Ukraine, and Moldova, more than any other. Its drainage basin extends into nine more.