The Donau (or Danube) is one of Europe’s major rivers, stretching some 2000 km through central and eastern Europe. It begins in Germany’s Black Forest and empties into the Black Sea. It is the second-longest river in Europe and the longest river in the European Union.
Along its course, the Donau passes through 10 countries, including Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, Moldova, and Ukraine. In most of its course, it forms the border between Austria and Hungary, and between Romania and Bulgaria.
The Donau has been a major commercial and cultural artery for centuries, serving as part of the patchwork of trading routes that stretched from the Baltic Sea to the Black Sea. Its main tributaries include the Ilz, the Inn, the Morava, the Tisza, the Sava, and the Prut.
One of its most iconic features is the 1508-meter Wachau Bridge (or Wachauer Brücke), which spans the Donau between Klosterneuburg and Tulln in Lower Austria. This spectacular bridge is the longest created by the renowned Habsburg engineering genius, Franz Anton Pilat. The bridge features three arches, as well as elaborate rock masonry featuring human figures, lions, medallions, and crests. It is also flanked by two stately towers, which were declared a UNESCO World Heritage Site in 1999.