To be privately owned
Spielberg Castle

Spielberg Castle, also known as Arbesser Castle, is a historic structure in Styria. It is situated on a hill and gave its name to the surrounding municipality.
History+
Spielberg Castle was built in 1570. Initially, only the dominion around the castle was referred to as Spielberg, before the name was adopted by the entire present-day municipality. The castle was associated with noble families such as the Teufenbachers, Heinrichsbergers, and Lachawitzers. Correspondence discovered in the castle from the 18th century provides insights into rural life in Upper Styria during that period. Since the early 19th century, the estate has been owned by the Arbesser-Rastburg family.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:AT-36598_Schloss_Spielberg_001.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: 47.2158, 14.7836