The remains of the Castle can be visited
Bibiton Castle (Ruin) (Kaltbrunn)

The Bibiton ruin in Kaltbrunn, Canton St. Gallen, was a lowland castle strategically located on the then Tuggenersee. Today, its remains in the Linth Plain are accessible to visitors.
History+
Bibiton Castle was likely built in the early 13th century by the Counts of Rapperswil. At that time, they were active as bailiffs of Einsiedeln Abbey and constructed several fortifications in the Linth Plain, including Grynau Castle. In the 14th century, Bibiton served as the seat for vassals of the Counts of Toggenburg. Documented residents include the knight Kraft Schnode in 1358 and the Austrian nobles von Bruchi until 1393. Later, the castle became the residence of the Meier von Kaltbrunn, mentioned in 1419 and 1428. The complex was destroyed in 1444 during the Old Zurich War and finally abandoned in the 15th 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: 47.2088, 9.0103