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

The Rothenfels ruin, a former hilltop castle, is situated on a wooded mountain spur northwest of Immenstadt in Oberallgäu. Once part of a double castle complex, it is now a freely accessible cultural monument.
History+
Rothenfels Castle was built in the second half of the 13th century by the Lords of Schellenberg. In 1273, the dominion passed to Rudolf von Habsburg before falling to Count Wilhelm II von Montfort in 1332. Together with the nearby Hugofels Castle, Rothenfels formed a double castle. A lightning strike destroyed the castle in 1462, but it was rebuilt. During the German Peasants' War in 1525, the double castle withstood a siege. In 1546, troops of the Schmalkaldic League occupied the complex. Count Ulrich von Montfort sold the fortress in 1565 to Johann Jakob von Königsegg.
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: 47.5690, 10.2049