Danube
Classified as an international waterway, it originates in the town of Donaueschingen, in the Black Forest of Germany, at the confluence of the rivers Brigach and Breg. The Danube then flows southeast for about , passing through four capital cities (Vienna, Bratislava, Budapest and Belgrade) before emptying into the Black Sea via the Danube Delta in Romania and Ukraine.
Danubian corridor
In paleontology and archaeology, the Danubian corridor or Rhine-Danube corridor refers to a route along the valleys of the Danube River and Rhine River of various migrations of Eastern cultures from Asia Minor, the Aegean region, the Pontic-Caspian steppe, etc., into the north and northwest of Europe.