The remains of the Castle can be visited
Lahr Castle

The Lahr Castle Ruin, known as the Storchenturm (Stork Tower), is a remnant of a medieval moated castle and serves as a landmark for the city of Lahr. Its architecture, which included a regular rectangular layout with four round corner towers, is an example of the late Staufer building type in Germany.
History+
Lahr Castle was constructed around 1220 by the Lords of Geroldseck. The Storchenturm, still standing today, was originally the northern tower of the complex. Its design with four round corner towers corresponded to a late Staufer type, which is rare in Germany and shows parallels to structures in Sicily.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Lahr_Storchenturm.jpg
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Location: 48.3390, 7.8723