To be privately owned
Katz Castle

Burg Katz, originally known as Burg Neukatzenelnbogen, is a hillside castle in St. Goarshausen, Rhineland-Palatinate. It stands above the Rhine and has been part of the UNESCO World Heritage Upper Middle Rhine Valley since 2002.
History+
The Counts of Katzenelnbogen had the castle built between 1360 and 1371, likely in response to the construction of the Electorate of Trier's Burg Maus, which was in direct proximity. Together with Burg Rheinfels on the opposite bank of the Rhine, Burg Katz formed a customs barrier and strengthened the regional castle network of the Katzenelnbogen family. After the extinction of this lineage in 1479, the castle passed to the Landgraves of Hesse. It was repeatedly the scene of inheritance disputes between the lines of Hesse-Kassel and Hesse-Darmstadt, leading to sieges and partial destruction in 1626 and 1647. The complex was also reinforced with additional fortifications. During the siege of Burg Rheinfels by the troops of Louis XIV in 1692, Burg Katz suffered further damage. After being conquered by the French in the Seven Years' War (1758) and returned (1763), the intact castle was blown up in 1806 on Napoleon's orders.
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: 50.1518, 7.7241