To be privately owned
Baldeney Castle

On the northern shore of Lake Baldeney in Essen is Baldeney Castle, a complex that emerged from a medieval moated castle. The structure, built from Ruhr sandstone, gave the lake its name and is now a protected architectural and archaeological monument.
History+
The origins of Baldeney Castle date back to 1226, when Count Adolf I von der Mark had a first fortified house built on this site, although a motte is presumed to have existed even earlier. The estate, originally a fief of Werden Abbey, was first documented in 1337 when Theodoricus von der Leythe and his son Everhard founded a chapel. Until 1432, the complex remained in the possession of the von der Leythe family, before passing through female descendants to various owners, including the von Vittinghoff and von Eyll families. In the 17th century, ownership changed again, until in 1747, Baron Franz Ernst von Bottlenberg, known as Schirp, acquired the castle. His family held the estate until 1968. The current appearance of the castle is the result of numerous alterations; the oldest preserved part is a residential tower from the 14th/15th century. Wings were added in the 17th and 18th centuries and redesigned in the 19th century. An outbuilding and a chapel were added later.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.de/thread.php?threadid=575
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: 51.4080, 7.0243