To be privately owned
Krempelstein Castle

Krempelstein Castle, also known as Krämpelstein or Schneiderburg, stands on a rocky outcrop above the Danube in Upper Austria. This complex once served as a toll station and retreat for Passau bishops.
History+
First documented in 1337, Krempelstein Castle came under the administration of ministerials of the Bishop of Passau from 1370. In 1782, it became part of Austria along with the Innviertel region. The castle initially served as a toll station and later as a residence for the Passau bishops. A notable episode in its history is the five-year imprisonment of Passau Cathedral Provost Dr. Rupert von Moosheim, who was held here due to his reformist views until his death in 1545.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.at/ooe/oberoesterreich.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: 48.5625, 13.5861