To be privately owned
Petronell Castle

In Petronell-Carnuntum, Lower Austria, stands Petronell Castle, an early Baroque building. As the successor to a medieval castle and a Renaissance palace, it stands today as a four-winged complex.
History+
The current appearance of Petronell Castle was created between 1660 and 1667 on behalf of the Abensperg-Traun family. Master builder Dominico Carlone created an early Baroque complex, the construction of which was shaped by numerous Italian craftsmen, including master stonemasons Ambrosius and Giorgio Regondi, stucco artists such as Giovanni Castello and Giovanni Piazoll, and the fresco painter Carpoforo Tencalla. In 1683, the castle suffered severe damage from a fire set by the Turkish army on its way to Vienna. From 1690, reconstruction took place under Otto Ehrenreich I von Abensperg-Traun, whereby the ceiling of the ballroom had to be re-frescoed as Tencalla's original had been destroyed.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Schloss_petronell.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: 48.1165, 16.8604