Castle On A Hill

This castle overlooks the Rhine River and in ancient times everyone going up or down the river had to pay a toll for the protection offered by the nobleman who lived there,  The trade moved peacefully on the river and the nobleman grew rich.
Pretty soon everyone wanted a castle on the Rhine and by the beginning of the 19th century there were 47 "toll booths" set up along the route, some of them less than a few hundred yards apart.