To be privately owned
Blühnbach Castle

Blühnbach Hunting Lodge is located in the Blühnbach Valley near Werfen, in the Salzburg Alps. This estate, now privately owned, was once an exclusive hunting domain.
History+
The origins of the castle date back to 1431, when a wooden hunting lodge was first documented at this location. Between 1603 and 1607, Prince-Archbishop Wolf Dietrich von Raitenau had the building expanded into a stone hunting lodge. After Salzburg's incorporation into Austria in 1816, ownership passed to the state treasury. In 1908, the Habsburgs acquired the property. Around 1910, Crown Prince Franz Ferdinand initiated a renovation and reconstruction of the hunting lodge. He also created an extensive, secluded hunting domain of 14,000 hectares.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Lplan / CC BY-SA 4.0 via Wikimedia Commons
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: 47.4804, 13.1049