To be privately owned
Lutter Castle

Burg Lutter, a castle complex, stands in Lutter am Barenberge in Lower Saxony. Originally designed as a moated castle, it served for centuries as an agricultural domain and is now an example of communal living and the preservation of a monument.
History+
First documented in 1259, the origins of Burg Lutter are presumed to date back to around the year 1000. It was long owned by the Bishop of Hildesheim and served as an administrative seat and border castle. In the 13th century, it was refortified and was the scene of sieges. After changing ownership, including the knightly family of Lutter and various noble families, the castle finally fell to the Duchy of Brunswick in 1523.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Burg_Lutter.jpg?uselang=de
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: 51.9864, 10.2706