Helga, When you look at the map of Europe you will see that the Rhine river starts in Switzerland, flows through lake Constance (Bodensee) the turns north and flows to the North Sea (part of the Atlantic ocean. The Danube (Donau) starts in the Black Forest in southern Germany – Baden Württemberg. It flows eastward through southern Germany and Northern Austria through Vienna, through part of Slovakia. Near Bratislava it turns south and goes through Hungary, eastward in Croatia, Serbia,Bulgaria, Romania and to the Black Sea in Ukraine. The Danube was only navigable from Ulm eastward, that’s why the settlers embarked there when they headed south eastward. Anne