Although the Rhine and Danube are both large rivers, the Danube is significantly larger. The Rhine runs for about 820 miles, while the Danube has a length of more than twice that -- 1,780 miles -- and is the second-longest river in Europe after the Volga. While both rivers pass through Germany and Austria, the Rhine also touches the countries of Liechtenstein, France, Switzerland and the Netherlands and the Danube runs through Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania and Ukraine.
The source of the Rhine River is the large Rheinwaldhorn Glacier in the Swiss Alps, and the river flows northwest from there until it empties into the North Sea. The Danube, meanwhile, forms with the meeting of the Breg and Brigach rivers in Germany's Black Forest and flows east into the Black Sea. The Danube has more than 300 tributaries branching off during its path -- more than seven times as many tributaries as the Rhine.
The Rhine is an important passageway for ship transports, particularly in Germany and France, and passes through some major cities, such as Basel and Rotterdam in the Netherlands and the German cities of Bonn, Cologne and Dusseldorf. The Danube also is a critical commercial route for Europe and it touches on Vienna, Austria; Budapest, Hungary; and Belgrade, Serbia -- each the capital of a country, so its importance to economic development is heightened.
The Danube has a much richer collection of wildlife than the Rhine, which suffered massive pollution in the 1970s and 1980s, harming many of its native species and killing some completely off. The Rhine has somewhere around 40 species of fish, for instance, while the Danube boasts more than 100. The Danube overall has more than 5,000 animal species, including approximately 180 breeding birds and 40 mammals. The Danube Delta is the last place in Europe where you can find a white-tailed eagle, and it features 60 percent of the world's white pelican population.
