Question: which country is the source of the river danube
Answer: As early as 1847 the following definition can already be found in the Universallexikon des Großherzogtums Baden ( Universal Lexicon of the Grand Duchy of Baden ) : `` Danube , the biggest river of Germany , rises at the Martinskapelle in a wild and lonely area of the Black Forest , is called Brege at its origin and forms the river Danube in Donaueschingen where it is unified with the Brigach .