To be privately owned
Frohsdorf Castle

In Lanzenkirchen-Frohsdorf, Lower Austria, stands Frohsdorf Castle. Originally built from the ruins of an older estate, it was redesigned several times and served as a residence for various noble families.
History+
The origins of Frohsdorf Castle date back to 1547, when it was built between 1547 and 1550 on the remains of the burned-down "Krotenhof". Christoph Teufel, the builder, later became a commissioner of the Lower Austrian knighthood. Following its destruction in 1683, a reconstruction and renovation in the Baroque style took place, with Count Franz Carl Hoyos having the castle redesigned according to plans by Johann Bernhard Fischer von Erlach.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Schloss_Frohsdorf_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: 47.7448, 16.2555