Source of the Danube
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." (German original: „Donau, der größte Fluß Deutschlands, entspringt bei der Martinskapelle in einer wilden und einsamen Gegend des Schwarzwaldes, heißt am Anfang Brege… und bildet erst in Donaueschingen, wo sie sich mit der Brigach vereinigt, die Donau.“)
Danube Valley Railway (Baden-Württemberg)
The Danube Valley Railway runs alongside the Danube river and crosses it several times. From Immendingen the line runs across the Upper Danube Nature Park "(Naturpark Obere Donau)", brushing up against the southern edge of the Schwäbische Alb, all the while following the course of the Danube. Between the towns of Inzigkofen and Herbertingen, the Danube Valley Railway again shares its tracks, this time with the Zollernalb Railway. At Ehingen (Donau), the line leaves what is known as the Danube valley today, and follows the valley formed by the Danube in times past, along the rivers Schmiech, Ach, and Blau. The railway again touches the border of the Schwäbische Alb between Allmendingen and Blaustein, and meets its eponymous river again at the line's terminus in Ulm.