To be privately owned
Gräfenthal Abbey

Gräfenthal Monastery, a former Cistercian abbey, is situated near Kleve in North Rhine-Westphalia, Germany. The complex, now known as Gut Gräfenthal, once served as an important burial site for nobles and nuns and was dedicated to Saint Mary.
History+
The foundation of Gräfenthal Monastery took place between 1250 and 1258 as a convent of the Cistercian Order. Count Otto II of Geldern initiated its establishment, with the name "Gräfenthal" deriving from the Latin term "vallis comitis" (valley of the count). The first nuns arrived from the Münsterabtei in Roermond. The monastery quickly flourished, supported by the Dukes of Geldern and Kleve, and often served as a provision for unmarried noblewomen. Until 1376, the monastery church was the final resting place for ten counts, countesses, and dukes of Geldern.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=566&hilight=Borghees
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: 51.7060, 6.1065