To be privately owned
Waldeck Castle

A historic hunting lodge, Waldeck Castle, was built in the late 18th century. Originally built for the Princes of Anhalt-Bernburg, its history is closely linked to a nearby mineral spring.
History+
The construction of Waldeck Castle took place in 1797. The builders were the Princes of Anhalt-Bernburg, who had the castle erected next to a mineral spring that had been reactivated in 1790. Between 1966 and 1967, the interior of the building underwent renovation.
Location+
Waldeck Castle is located in Diez-Geilnau in the Rhein-Lahn district, a region in Rhineland-Palatinate, Germany. It is situated at an elevation of approximately 104 meters above sea level.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=932
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: 50.3538, 7.9390