To be privately owned
Hambach Castle

In Niederzier, North Rhine-Westphalia, Hambach Castle is a hunting lodge of the Dukes of Jülich. Originally a rectangular four-wing complex with four corner towers, parts of two wings and three towers remain today. The two towers flanking the entrance have been converted into living spaces.
History+
The castle's origins trace back to a fortress built around 1280 by Count Walram of Jülich. In December 1512, a gunpowder explosion destroyed the structure, which was subsequently rebuilt and expanded by Duke Johann. Between 1558 and 1565, Duke Wilhelm V of Jülich-Kleve-Berg commissioned architects Alessandro and Maximilian Pasqualini to transform the estate into a Renaissance castle. It then served as a venue for hunting parties in the Hambach Forest. In 1659, the castle hosted the state parliament of the Duchy of Jülich. In the 18th century, it functioned as an electoral pleasure palace before being converted into a monastery in 1769. The French declared it national property in 1794 and sold its inventory from 1801 to 1805, also demolishing the north tower and the northwest wing.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=570
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: 50.8999, 6.4407