The Ruin can be visit.
Riedburg Castle (Ruin) (Köniz)

In the Swiss municipality of Köniz in the canton of Bern is the Riedburg ruin, a 14th-century castle ruin.
History+
The construction of Riedburg is dated around the year 1350. It served as the ancestral seat of Ivo von Bolligen, whose dominion extended over the surrounding lands between the Sense and Scherlibach rivers. However, its existence was short-lived, as the castle fell victim to a conflict between Bern and Fribourg in 1386 and was destroyed by Fribourg troops. From 1388, the Riedburg lordship came into the possession of the city-state of Bern.
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: 46.8653, 7.3650