The remains of the fortress can be visited
Fort Claudia

Fort Claudia, also known as “Hochschanz,” is a fortress in Tyrol, Austria. It was constructed in the 17th century as a component of the defensive system around Ehrenberg Castle. Situated at an elevation of approximately 1096 meters above sea level, the facility was designed to prevent circumvention of the main castle.
History+
Planning for Fort Claudia began around 1639 under the direction of the state fortress master builder Elias Gumpp. The construction was a response to the vulnerability of the Falkenberg, opposite Ehrenberg Castle, identified in the 16th century. The fortress was named after the then-ruling Duchess Claudia von Medici. Despite this fortification, the Bavarian Elector managed to capture Ehrenberg Castle during the War of the Spanish Succession (1703). However, the Tyroleans soon recaptured the castle by moving artillery to the then-unfortified Schlosskopf and bombarding the castle into submission.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Fort_Claudia_5.jpg
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: 47.4619, 10.7228