To be privately owned
Helfenberg Castle

Helfenberg Castle, also known as Revertera Castle, is a castle complex in the Mühlviertel region of Upper Austria. It is at an altitude of approximately 633 meters above the village of Helfenberg and is an example of 17th-century architecture, currently in private ownership.
History+
Helfenberg's origins date back to the 13th century, when a castle was built around 1250 and later expanded. The first documented mention of an owner, Wirint de Helfenberch, dates to around 1224. The property changed hands multiple times, including the Lords of Piber, the Neundlinger family, and Erasmus Greisenecker. Following inheritance disputes, the castle passed to Christoph Künast in 1586, who then sold it. A phase began in 1593 with the Lords of Ödt zu Götzendorf, who had the castle completely rebuilt in 1607, giving it its current appearance. The tower construction had already been planned as an extension during the Piber era.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Schloss_Helfenberg-1.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: 48.5433, 14.1369