To be privately owned
Wolfsberg Castle (Ermatingen)

Wolfsberg Castle, a historical structure, stands above Ermatingen in the canton of Thurgau. Originally built in the 16th century, it underwent several transformations and expansions over time, which gave it its distinctive appearance today.
History+
The castle's origins date back to 1571 when Wolf Walter von Gryffenberg had a cube-shaped building constructed. In 1731, Junker Johannes Zollikofer acquired the estate and extensively remodelled it, giving it its current form. The southern Parquinhaus was likely built in 1795 by Junker Jakob Högger von Höggersberg and was converted into a guesthouse in 1824 by Colonel Charles Parquin, though it closed in 1839. Later owners included Joseph Martin Parry, who developed the estate into a model agricultural enterprise, and Karl Bürgi, who established a spa house around 1865, which operated until 1918.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 47.6587, 9.0787