The Danube is an international river located in Central and Eastern Europe. It rises in Germany's Black Forest and flows for a distance of 2,860 kilometres (1,780 mi) through ten countries before emptying into the Black Sea. Its drainage basin is home to over 280 million people, with an average population density of 18.4 people per square kilometer. It is the most internationally shared river in the world, with four nations having a direct access to the river.
The Danube is one of the major navigable rivers of Europe and a busy international shipping route. The lower Danube flows through Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova, and Ukraine before emptying into the Black Sea. The upper Danube flows through Germany, Switzerland, Austria, Slovakia, and the Czech Republic. Many Danube cities, including Vienna, Budapest, Bratislava, and Belgrade, have played important roles in the development of European history and culture.
The Danube is also a major source of hydroelectricity, as well as water for crop irrigation, navigation, and other uses. In addition, the river provides habitat for a variety of animal and plant species. The river is home to numerous protected areas and is a major tourist destination.