To be privately owned
Groppenstein Castle

Northwest of Obervellach, on a rock above the village of Raufen in Carinthia, Austria, stands Groppenstein Castle.
History+
Groppenstein Castle was first documented in 1254 as “turris Cropensteine,” when Archbishop Philipp of Salzburg granted possessions to Heinrich Swärhaupt. A ministerial named Pabo de Cropensteine witnessed this enfeoffment. The castle tower itself might be older, with its name derived from the Old High German personal name Groppo. By the end of the 13th or beginning of the 14th century, Groppenstein came into the possession of the Counts of Görz. In 1342, it was already referred to as a fortress. Between 1470 and 1480, it was expanded into a late medieval defensive complex by Görz ministerials, with Jakob Gröppel von Groppenstein constructing the current palas. After the death of Veronika von Groppenstein, the last of her lineage, in 1486, the property passed to her sons. Later, Emperor Maximilian I enfeoffed Christoph Graf with the castle. The castle changed hands multiple times, including to the Khevenhüller, Hollenegg, and von Lind families. From 1693 to 1870, the Barons von Sternbach were the owners.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Obervellach_Burg_Groppenstein_08042007_63.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: 46.9417, 13.1825