To be privately owned
Landesburg Castle (Lechenich)

In Lechenich, located in the Rhein-Erft district of North Rhine-Westphalia, Landesburg Castle was once one of the most powerful castle complexes in the Rhineland. Originally conceived as a moated castle and built of brick in the 14th century, it served as a residence and administrative center for the Archbishops and Electors of Cologne.
History+
The history of Landesburg Lechenich begins with a predecessor complex, first mentioned in 1138. This older castle, built on a motte with a residential tower and surrounded by wide moats, was besieged several times in the 13th century but never captured. Pledged after the Battle of Worringen in 1289, it fell victim to a royal order for destruction in 1301, and rebuilding was prohibited in 1302. From 1306, Archbishop Heinrich II von Virneburg began construction of the current Landesburg. The residential tower was built between 1306 and 1317, and under his successors, the complex was expanded into a fortress-like castle, protected by double moats and the fortified city. The castle was a residence and administrative center, also the scene of meetings and receptions for high-ranking guests such as King Sigismund and Emperor Charles V. During the Thirty Years' War, the castle was besieged in 1642 but not captured.
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: 50.8019, 6.7685