Speaking of the Rhine, if you are ever in Germany you may want to visit the stretch between Boppard am Rhein and Koblenz. The UNESCO world heritage status of the region is not accidental: both the river and the surrounding landscape are very worthwhile, as are the many castles along the route.
The Rhine River is a central European river the flows to the Northwest from Switzerland, where it passes through Germany, France and the Netherlands finally ending in the North Sea. The Rhine is also technically a tributary to the Danube, via the Rhine-Danube main channel that is 106 miles or 171 km long. The Rhine itself is 766 miles or 1233 km long.