To be privately owned
Neu-Wartenburg Castle

Neu-Wartenburg Castle, built in the 18th century, stands on the right bank of the Vöckla River in Upper Austria. It serves today as a private residence.
History+
The history of the Wartenburg dominion, to which the later Neu-Wartenburg Castle belonged, dates back to 1128, when Arnold von Wartenburg was first mentioned in a document. For over 300 years, the Lords of Pollheim shaped the region, starting with Ortolf von Pollheim in 1319. Wolfgang von Polheim founded the first Paulaner monastery in the German-speaking world in the late 15th century. During the Counter-Reformation, the Protestant Ludwig von Pollheim sold the dominion around 1640 to the Catholic Tobias Nütz von Goisernburg, who converted the fief into free property.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Schloss_Neu-Wartenburg.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: 48.0116, 13.6229