Danube
The Danube was once a long-standing frontier of the Roman Empire, and today flows through 10 countries, more than any other river in the world. Originating in Germany, the Danube flows southeast for , passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is home to fish species such as pike, zander, huchen, Wels catfish, burbot and tench. It is also home to a large diversity of carp and sturgeon, as well as salmon and trout. A few species of euryhaline fish, such as European seabass, mullet, and eel, inhabit the Danube delta and the lower portion of the river.
Danube Valley Railway (Baden-Württemberg)
The Danube Valley Railway (German: Donautalbahn or Donaubahn) in Baden-Württemberg in south-western Germany is a 133.8-kilometre-long railway running from the city of Ulm to Immendingen, which is largely single-tracked and for the most part not electrified. The line is famous especially for its charming course through the Upper Danube Nature Park ("Naturpark Obere Donau"), and is particularly attractive to bicycle tourists. The Royal Württemberg State Railways and the Grand Duchy of Baden State Railways built the line as part of the railway projects undertaken between 1865 and 1890. The construction of the section between Tuttlingen and Inzigkofen was pushed through by the German general staff, for whom the Danube Valley Railway was seen as a strategic railway in case of another war with France. Since 1901, the Danube Valley Railway, together with the Höllentalbahn (Schwarzwald), form part of the pan-regional railway link from Ulm to Freiburg im Breisgau.