To be privately owned
Tralau Castle

Tralau Castle, located in Travenbrück-Tralau in Schleswig-Holstein, is a structure that, despite its actual function as a manor house, is referred to as a castle due to its appearance. It is an example of late Historicist architecture.
History+
The history of the Tralau area dates back to its first documented mention in 1197. In the Middle Ages, a rampart castle in the border region between Saxon and Wendish territories served for defense. A knightly family, named after the seat, remained there until the early 15th century. In 1444, the Brockdorff family took over the property, which developed from a manorial estate into a farming estate. After about two centuries, the Rantzaus followed in 1647, selling the estate in 1702. The 18th and 19th centuries were marked by frequent changes of ownership, including the Dukes of Plön (1754-1781) and the Buchwaldt family (1824-1855).
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Schloss_Tralau.JPG
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: 53.8366, 10.3045