To be privately owned
Haseldorf Castle

In the municipality of Haseldorf in Schleswig-Holstein stands Haseldorf Castle, a classical building. Originally built in 1804 according to plans by the Danish master builder Christian Frederik Hansen, the castle is a single-story brick building with corner projections and a two-story central projection.
History+
The diking of the Haseldorf Marsh began as early as the 12th century. A first castle was built in 1184 by the Archbishop of Bremen, but was destroyed in 1258 and rebuilt in 1317. The bailiwick of Haseldorf fell to King Christian I of Denmark in 1460. In 1494, King John I sold the bailiwick to Knight Hans von Ahlefeldt. During the Thirty Years' War, the castle was destroyed in 1627 by Wallenstein's troops. The von Schilden family acquired the estate from the Ahlefeldts in 1731. The current castle was built in 1804 for Hans Heinrich von Friccus-Schilden. A grand staircase and dormer windows were added in the late 19th century. In 1896, the Haseldorf estate passed to Prince Emil von Schoenaich-Carolath-Schilden, who turned the manor house into a literary meeting place. Rainer Maria Rilke was among the guests.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Haseldorf_Herrenhaus.jpg
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: 53.6326, 9.5977