The remains of the Castle can be visited
Ratzenried Castle (Ruin)

Once known as the Upper Castle, the Ratzenried Ruin is a historic site on a mountain spur near Ratzenried in the Ravensburg district, Baden-Württemberg.
History+
The construction of Ratzenried Castle is dated to the beginning of the 12th century, with the Lords of Ratzenried first mentioned in documents in 1145. Its function was possibly to secure the fiefs and tributes of St. Gallen Abbey in the region. After the extinction of the original Ratzenried line at the end of the 13th century, new lords adopted the name and the castle, but lost it around 1350. From 1353, the Lords of Molpertshausen were the castle owners, and in 1369, Hans von Molpertshausen was officially enfeoffed by the Abbot of St. Gallen. After further changes of ownership, the castle passed to the Humpis of Ravensburg in 1453, who called themselves Humpis of Ratzenried from the 16th century onwards.
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: 47.7129, 9.9009