The Fortress can be visited
Fortress Germersheim-Zeughaus

The Armory (Zeughaus) in Germersheim, Rhineland-Palatinate, Germany, is a structure. As part of the former Royal Bavarian Fortress, it played a role in the German Confederation's defensive strategy against potential French attacks.
History+
The origins of Germersheim's fortifications date back to 1792, when the French took over the city and erected new structures. These were reinforced after the Bavarian takeover in 1814. In 1815, the German Confederation recognized Germersheim's strategic importance as a hub for troop concentration in the event of a French attack. Initial survey work began in 1818, but the decision to build a fortress was made only in 1832. Under the direction of Friedrich von Schmauß, construction commenced in 1834 with the excavation of the main moat.
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: 49.2215, 8.3757