Four capital cities, Vienna, Bratislava, Budapest and Belgrade, reside on the Danube River. The Danube River is the second longest river in Europe after the Volga River. The Danube courses through 10 countries, spans thousands of miles and processes water from nearly 20 different countries, making it an important river to the European continent.
The Danube River begins in Germany, and it divides into three distinct basins, classified according to differing river gradients. The Upper Basin includes the portion of the Danube that runs through Germany and Slovakia. The Upper Basin passes through the German capital of Vienna and the Slovakian capital of Bratislava before joining with the Middle Basin in Bratislava. The Middle Basin covers the largest distance of the three river basins, and it extends to the borders of Serbia and Romania. The Middle Basin passes through the Iron Gate Gorge, then empties into the third basin, the Lower Basin, which includes the lowlands, mountain ranges and flat plateaus in Romania.
The Danube River, although shorter than the Volga, crosses many more national boundaries. The Danube provides several important benefits to Europe, including facilitating transportation and commerce, attracting tourists and benefiting economies by enabling fishing and agriculture. Over 80 million people live around the Danube River and contribute to the area's diversity with many languages and cultures.