The Castle can be visited
Pfalzgrafenstein Castle

Pfalzgrafenstein Castle, also known as the Pfalz near Kaub, is a toll castle in the Rhine near Kaub in Rhineland-Palatinate, Germany. Its location on a rocky island makes it a landmark of the Upper Middle Rhine Valley and one of the few undestroyed structures of its kind in the region.
History+
The castle's origins trace back to a tower built by Louis IV, Holy Roman Emperor, between 1326 and 1327. As Count Palatine of the Rhine and later Roman-German Emperor, he used the castle to secure and monitor toll revenues on the Rhine. Pfalzgrafenstein never served as a residence. Between 1339 and 1342, the complex was supplemented by a twelve-meter-high curtain wall. In the 15th century, the tower was presumably raised with half-timbering and corner turrets. To counteract damage from ice floes, a pointed reinforcement was added to the upstream side of the castle in 1606/1607, giving it its current ship-like appearance.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: © BraCom (Bram)
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 50.0831, 7.7656