The remains of the Castle can be visited
Grottenstein Castle (Ruin) (Haldenstein)

The Grottenstein ruin, a historic castle ruin, is located in the municipality of Haldenstein in the Swiss canton of Graubünden. It is one of three castles in the municipality and is located in a spacious rock shelter at the foot of a cliff face.
History+
The first documented mention of Grottenstein Castle occurred in 1672. However, the name "Grottenstein" appeared earlier in chronicles, likely referring to the toads living under the rock overhang. It is presumed that due to its geographical position, the castle was among the early possessions of the Lords of Lichtenstein, first mentioned around 1180. The exact construction period and the sequence of castle constructions in the region cannot be definitively determined without archaeological excavations.
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: 46.8839, 9.5228