danube

The Danube is Europe's second-longest river, with an estimated length of about 2,860 kilometers (1,777 miles). It rises from the confluence of the Brigach and Breg rivers at Donaueschingen in the Black Forest, Germany, and flows generally southeastward to the Black Sea. Along its course it passes through or borders ten countries, namely Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, Moldova, and Ukraine, before reaching the Danube Delta and the coast of the Black Sea. The Danube's drainage basin covers roughly 817,000 square kilometers.

The river's valley hosts major urban centers such as Vienna, Bratislava, Budapest and Belgrade and it is an important navigation route for freight and passengers for much of its length. The Rhine–Main–Danube Canal connects the river to the North Sea, making it part of a continuous inland-waterway system from the western to the Black Sea. The Danube Basin also supports agriculture, energy production, tourism and fisheries. International cooperation through the ICPDR coordinates environmental protection and flood management across borders.

Historically, the Danube has been a strategic corridor for trade, migration and cultural exchange, shaping the identities of many Central and Eastern European communities. Parts of the river landscape are protected as UNESCO World Heritage sites, including the Wachau cultural landscape in Austria and the Danube Delta in Romania. The river has featured in literature, art and music, notably in the popular waltz The Blue Danube by Johann Strauss II.