To be privately owned
Gräfgenstein Castle

Gräfgenstein Castle, also known as Griffgenstein, is a partially preserved medieval hilltop castle in Ratingen-Eggerscheidt. It once served as a strategic point at an important ford.
History+
The exact date of Gräfgenstein Castle's construction is not historically documented, but its founding is presumed to be in the 13th century. It functioned as a ministerial seat and military stronghold for the Counts of Berg. In the 15th century, the complex is mentioned in documents as Griffgenstein. In 1860, the castle passed into the possession of the Counts of Spee.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=583
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: 51.3111, 6.8947