To be privately owned
Grub Castle

Grub Castle is situated on the eastern shore of Lake Hallstatt in Upper Austria. Originally a farmhouse, it evolved into a building.
History+
The origins of Grub Castle date back to 1522, when a farmhouse named “Gut in der Grub” stood on this site. In 1622, it came into the possession of the Eysselsberg family. Mathias von Eyselsberg, market judge of Hallstatt, donated the Trinity altar in St. Michael's Church in 1652. His descendant Christoph Eyssel von Eysselsberg acquired the castle in 1658 and had a crypt built in the parish church of Hallstatt. In 1704, ownership passed to Johann Gottfried Etzinger, the salt administrator and market judge of Hallstatt, whose son later donated the Trinity Column in Hallstatt's market square. Between 1864 and 1890, the castle belonged to Tsar's ambassador Alexander Tschaffkini, who had it redesigned in a historicist style in 1868.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Obertraun_Schlo%C3%9F_Grub.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: 47.5621, 13.6642