The Danube is the second longest river in Europe and almost 3000 kilometres long. It rises in Germany, more precisely in Baden-Württemberg, and flows into the Black Sea. On its way, it flows through many countries in Central and South-Eastern Europe: Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, the Republic of Moldova and Ukraine. Four capitals also lie on the Danube: Vienna, Bratislava, Budapest and Belgrade.
The ancient Romans already knew the Danube and called it Danubia. At that time, it was the northern border of the Roman Empire for a long time. Later, parts of the river were also a border, for example between Austria-Hungary and the Ottoman Empire. But the Danube did not only separate countries and peoples: it has always been one of the most important waterways through Europe.
The Danube flows mainly through flat landscapes. In some places, however, it also has to pass through narrow mountain valleys. The most famous narrow point is the "Iron Gate" on the border between Serbia and Romania: Here the river breaks through the Carpathian Mountains.
Before it flows into the Black Sea, the Danube divides into a widely ramified delta with many tributaries. It is one of the largest nature reserves in Europe, about twice the size of Saarland. UNESCO declared it a World Heritage Site in 1991 so that it could be better protected.
The Danube Cycle Path runs along the Danube. It runs from the source of the Danube to its mouth in the Black Sea and is a popular long-distance cycle route. On and along the Danube, rulers have travelled with their entourage since Roman times. This was much more pleasant than travelling by land, because the roads were very poor. Today, the Road of Emperors and Kings is a popular tourist route. Travelling by boat is also popular. In the high season, more than 70 cruise ships sail on the Danube.