Danube River

The Danube is Europe’s second longest river after the Volga. It starts in Germany’s Black Forest where the Brigach and Breg rivers join up at Donaueschingen. The river then flows eastward for about 2,850 km (~1,771 miles) before it empties into the Black Sea. There are around 300 tributaries.

The river flows through, or is part of the border, of 10 different countries: Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova, and Ukraine. However, the river is not known as the Danube in any of these countries.

English uses the French word “Danube”. In Germany and Austria is the Donau, in Slovakia it is the Dunaj, in Hungary it is the Duna, in Croatia, Serbia and Bulgaria it's called the Dunav, in Romania and Moldova it called Dunărea and in Ukraine it is the Dunai. I still just call it the Danube.

The upper Danube is an important source of hydroelectricity and the lower Danube is a major avenue for freight transport. In 1992, a canal was completed on the Main River, linking to the Danube, allowing traffic to flow between the North Sea and the Black Sea.

The river is also an important water supply for irrigation and fishing. It contains 7 different species of fish that are not found anywhere else on Earth. It provides drinking water for over 10 million people, especially in Germany. However, the water is highly polluted in Austria and in Hungary; it becomes drinkable again in parts of Romania.

This summer I want to do one of the day cruises between Budapest & Bratislava or between Bratislava and Vienna. Here's a picture of the river in Budapest.
Most people are at least somewhat familiar with Johan Strauss' famous 1867 An der schönen, blauen Donau - The Blue Danube waltz which became one of the symbols of imperial Vienna.