The remains of the Castle can be visited
CastleRöhrnbach
Kaltenstein Castle (Ruin)

The Historic Building+
History+
Construction and Early Years
The castle was built in 1389 by the Prince-Bishops of Passau. It has been abandoned since the end of the 17th century and finally fell into disrepair after 1822. In 1975, the tower was erected from its remains.
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: 48.7319, 13.5337