To be privately owned
Campen Castle

Campen Castle, also known as Campen Palace, is a lowland castle in Flechtorf, a district of the municipality of Lehre. Originally built to protect a trade route, it is now privately owned.
History+
The first documented mention of Campen Castle occurred in 1279, when it was conquered by Duke Henry the Wondrous and Duke Albert the Fat during a dispute with Bishop Otto I of Hildesheim. However, the complex was probably built earlier on an island surrounded by two arms of the Schunter River. The Welf ministerialis family of Blankenburg, who received the castle as a fief, subsequently named themselves after it. The castle changed hands several times, often through pledges by the Dukes of Braunschweig. Between 1585 and 1596, under Duke William the Younger, the castle was expanded into a palace complex.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Burg_Campen_Hauptgebaeude.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: 52.3524, 10.7093