The Castle can be visited
Riom Castle

Riom Castle, a castle complex in the canton of Graubünden, is an example of late medieval secular architecture and today a cultural venue.
History+
The origins of the site date back to the mid-9th century, when a royal court existed here. Around 1240, the construction of Riom Castle is attributed to the Lords of Wangen-Burgeis. However, this rule met with resistance from the Bishopric of Chur, as it threatened its access to pass routes and possessions. In 1258, Berall von Wangen-Burgeis sold the castle, presumably under pressure, to the Bishop of Chur. From then on, Riom served as the seat of the bailiffs who exercised high jurisdiction in Oberhalbstein. In the 14th and 15th centuries, the castle was repeatedly pledged. After the valley bought itself free from episcopal rights in 1552, the castle lost its political significance and was uninhabited after the 16th century.
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: 46.6092, 9.5843