To be privately owned
Weißenegg Castle

The Weißenegg castle ruin, a former twin castle dating back to the first half of the 12th century, is now partially in ruins. Its remains are widely visible and are protected as a historical monument.
History+
The history of Weißenegg Castle is closely linked to the Weißenegger family, who likely had their ancestral seat here. An early representative was Wülfing von Wizzeneck around 1120. The first documented mention of the castle occurred in 1243 as “dominus de Wizenekke”. The Weißeneggers were a noble family in Carinthia during the 13th and 14th centuries, even providing bishops. From 1300, Weißenegg served as the seat of a regional court. In 1332, ownership passed to the Lords of Walsee, who bequeathed it to the Counts of Cilli in 1363. They exchanged the castle with the Diocese of Bamberg in 1425, remaining in its possession until 1759. Subsequently, it became part of the Austrian Empire.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Ruden_Weissenegg_01.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: 46.6651, 14.7791