The Fortress can be visited
Fortress Germersheim-Stengelkaserne

The Germersheim-Stengelkaserne Fortress is a structure in Germersheim, Rhineland-Palatinate, Germany. As part of the former Germersheim Fortress, it once served defensive purposes and now stands as 19th-century Bavarian military architecture.
History+
The Germersheim Fortress, which included the Stengelkaserne, was financed by the German Confederation and constructed between 1834 and 1861. Its primary role was to protect against potential French attacks in western Germany. Germersheim was chosen as a military hub due to its location on the Rhine.
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: 49.2193, 8.3683