To be privately owned
Stammeln Castle

Burg Stammeln, once designed as a moated castle, combines historical architecture with modern use. Its history dates back to the 15th century.
History+
The earliest mention of Burg Stammeln can be found in the Jülich Knight's Roll of 1460, where Wilhelm Schilling von Gustorf is named as the owner of an estate in Stammeln. Through the marriage of Katharina von Schilling, the property passed to Andreas von Randerath, who expanded the complex in 1583. In modern times, the castle remained in the possession of the descendants of the sugar manufacturer Valentin Pfeifer until 1962, with his granddaughter Hedwig von Gienanth being the last owner from this family.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 50.9164, 6.6257