To be privately owned
Rheineck Castle

Rheineck Castle, a hilltop castle in Rhineland-Palatinate, is situated above Bad Breisig on the left bank of the Rhine. Its history dates back to the 11th century.
History+
The origins of Rheineck Castle lie in a complex from the 11th century, built by the Rhenish Palatine Counts, which formed the center of the Rheineck Burgraviate. In the 12th century, Otto von Salm was the first to call himself "Count of Rheineck." After its destruction in 1151 by King Konrad III, the Archbishop of Cologne, Rainald von Dassel, claimed the castle as part of his domain. To preempt the ambitions of Count Palatine Konrad von Hohenstaufen, Rainald ordered the occupation and reconstruction of the castle in 1166, thereby preventing an impending civil war. Around 1180, the knightly family of Ulmen was enfeoffed with the castle, later adopting the name of Rheineck. After the extinction of this family in 1539, the Burgraviate passed to the Barons of Warsberg and later to the Counts of Sinzendorf. In the 1830s, a reconstruction of the castle took place on the old foundations, after it had been destroyed multiple times.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Joachim Schneeleopard
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: 50.4959, 7.3130