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.
Danu (Irish goddess)
The etymology of the name has been a matter of much debate since the 19th century, with some earlier scholars favoring a link with the Vedic water goddess Danu, whose name is derived from the Proto-Indo-European root "*dʰenh₂-" "to run, to flow", which may also lie behind the ancient name for the river Danube, "Danuuius" – perhaps of Celtic origin, though it is also possible that it is an early Scythian loanword in Celtic.