The remains of the Castle can be visited
Arnulfsfeste Castle

Northwest of Moosburg's Mitterteich in Carinthia, Austria, the Arnulfsfeste castle ruin, also known as Hetzelburg, is on three hills. The complex has a history dating back to the Bronze Age.
History+
The first documented mention of Arnulfsfeste dates back to 879. After 1100 until the second half of the 15th century, the Counts Palatine of Görz were the owners, before the Habsburgs took over. From 1501 to 1630, the Ernauer family followed, from 1633 the Barons of Kronegg, and finally from 1733 the Counts of Goëss. With the construction of a new castle at the beginning of the 16th century, the decay of Hetzelburg began.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://www.wehrbauten.at/ktn/kaernten.html
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: 46.6604, 14.1582