To be privately owned
Ehrenburg Castle (Ruin) (Plaue)

The Ehrenburg ruin, a former hilltop castle, stands on the western slope of the Geratal valley above the town of Plaue in the Ilm district of Thuringia. It is now privately owned and not publicly accessible.
History+
The construction of Ehrenburg took place after 1324 under the patronage of the Counts of Schwarzburg. Towards the end of the 15th century, the castle lost its significance and began to fall into disrepair. Initial measures to secure the masonry were carried out in 1856. In 1912, the castle changed hands, and a restaurant was established within its walls.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 50.7793, 10.8957