To be privately owned
Greifenthurn Castle

In the north of Feldkirchen in Carinthia, Austria, is Greifenthurn Castle, a cubic building with a half-hipped roof. It was built in the first half of the 16th century and served as a residence for various families.
History+
Greifenthurn Castle was constructed in the first half of the 16th century. From the early 17th century, for about one hundred years, it was the ancestral seat of the Forchegger family. Hieronimus Forchegger served as a councilor and merchant around 1604 and became a Bamberg official from 1618. In the 18th century, the property's use changed, and it served as the residence for ironmasters.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Feldkirchen_Gurktslerstrasse_37_Schloss_Greifenthurn_10062011_111.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: 46.7307, 14.0955