The Fortress can be visited
Federal Fortress Ulm-Vorwerk Schwaighofen

The Vorwerk Schwaighofen, part of the Federal Fortress of Ulm, was built in the 19th century and is located in Neu-Ulm, Bavaria, Germany.
History+
The Federal Fortress of Ulm, to which the Vorwerk Schwaighofen belongs, was one of five federal fortresses financed and built by the German Confederation in the 19th century. After Napoleon's defeat in 1815, the need to secure the territories both externally and internally was recognized. Construction of the Federal Fortress of Ulm lasted from 1842 to 1859. The Vorwerk Schwaighofen itself was built between 1850 and 1853 under the direction of Bavarian First Lieutenants Belleville and Knollmann. It was designed to accommodate up to 231 soldiers and was strategically located approximately 250 meters in front of the salient of Bastion 3.
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: 48.3929, 10.0140