Burg Pfalzgrafenstein

Across the river from the village of Kaub, the boat-shaped toll castle Pfalzgrafstein, built in 1326, perches on an island in the middle of the Rhine. A once-dangerous rapid here (since modified) forced boats to use the right-hand side of the river, where a chain forced ships to stop and pay a toll. Pick up an audioguide to learn more about its lengthy history. It's reached by the Fährboot passenger ferry, next to Kaub's car ferry dock.