With a length of 2,857 kilometres, the Danube is the second longest river in Europe after the Volga. The name comes from the union of the two headwaters Breg and Brigach, which have their source in the central Black Forest in the southwest of Baden-Württemberg. As a result, it crosses the large basin landscapes of the northern Alpine foreland and the Vienna Basin (upper reaches), the Pannonian Plain (middle reaches) and the Romanian Plain (lower reaches). In an extensive delta, the Danube in Romania flows into the Black Sea. On its course, the Danube crosses the ten riparian countries Germany, Austria, Slovakia (picture), Hungary, Serbia and Romania, as well as Croatia, Bulgaria, Moldavia and the Ukraine.
Like all waters, the Danube has a positive effect on viticulture and creates the conditions for this by forming often terraced valley slopes. On its banks or in its catchment area, as well as on several tributaries, there is significant viticulture in a total of five countries. In Germany there is only a small area of vineyards near Bach on the Danube between Regensburg and Straubing; the wine is marketed under the name Regensburger Landwein. In Austria, these are the wine-growing regions of Carnuntum, Wachau and Wagram (Klosterneuburg area), which the river crosses, and the three wine-growing regions of Kamptal, Kremstal and Traisental, which are named after tributaries of the Danube.
In Hungary, viticulture is practised almost everywhere along the Danube between Visegrád (Plintenburg) north of Budapest and the southern border. In Slovakia, the vineyards are mainly located on the three Danube tributaries Hron (Gran), Nitra (Neutra) and Váh (Waag) around the capital Bratislava. In Romania, the Danube forms the border in the region of Dobrogea in the extreme southeast on the Black Sea. The shipping route Rotterdam-Constanța is the shortest navigable connection between the North Sea and the Black Sea via the Rhine, Main, Main-Danube Canal, the Danube and the Danube-Black Sea Canal. See other rivers under Waters.