The central Rhine valley is perhaps the most enchanting region along the entire river stream. Near the city of Bingen in Germany the Rhine enters a valley. Hereon, up to Koblenz (about 65 kilometers downstream), the river flows through the valley. Eons of erosion have created characteristic landscapes in the valley. At times sheer cliffs hewn in and at other times gentle slopes line the banks of the river. To keep an eye on the traffic along the river, many castles were built on the hilltops along the river banks. The central valley has 40 such castles. Due to the warm weather, the land in the valley is suitable for the cultivation of grapes. Hence, the slopes of the mountains along the route are dotted with vineyards. The wine from the valley too, is well-known. As a result of such natural and cultural features, the valley has been declared a World Heritage Site.