To be privately owned
Bossee Manor

Gutshaus Bossee is a manor house in Schleswig-Holstein. Its origins date back to the 15th century.
History+
The history of Gut Bossee began after the destruction of medieval castles and the end of the Westensee knightly lineage. The von Ahlefeld family chose this location as their new residence, and Bossee was first documented as their manor in 1470, making it the oldest estate in the region. From this early period, the vaulted cellar beneath the current manor house is still preserved. The first manor house was built in the 16th century. Under the Rantzau family, the estate acquired its extensive farm buildings, which are still visible today.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://schloesserrundschau.de/schleswig/schloesser/rendsburg31.html
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: 54.2866, 9.8959