To be privately owned
Zelhem Castle

Zelhem Castle, a former knight's seat, is situated in the Düffel between the villages of Mehr and Niel. Its history dates back to the 12th century.
History+
Zelhem was first mentioned as an estate of Echternach Abbey in the 12th century. In the early 14th century, the complex was part of the Kleve landholding of Kranenburg before being sold to the Lords of Groesbeek in 1348. In the 15th century, the noble residence passed into the possession of the Palant-Wylich family, who held it for several centuries. The current building fabric primarily dates from the first half of the 15th century but was redesigned in the Renaissance style around the mid-16th century. Around 1800, the castle underwent a significant reduction in its structure, being scaled back to just the main wing.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=566&hilight=Borghees
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: 51.8184, 6.0314