Fort Thüngen was built in 1732, when the Austrian authorities decided to reinforce the fortress of Luxembourg. In 1836, and then from 1859 to 1860, the fort was modernised, expanded and reinforced, this time under the authority of the Prussians. Together with Fort Olizy and Fort Parkhöhe, Fort Thüngen forms the outer girdle of the Grünewald front.
Nowadays, Fort Thüngen is the only detached fort still standing on the site of the former fortress of Luxembourg. While parts of the above-ground construction have been destroyed, almost everything below has remained intact.
In 1980, initial works aimed at restoring the Thüngen redoubt were undertaken by the ARBED Anti-Crisis Division (Division Anti-Crise - DAC), led by Jean-Pierre KOLTZ.
In 1990/1991, the fort was entirely uncovered so the site could be studied and the extent of the remains assessed.
In 1994, the old quarters and fortifications of the City of Luxembourg were listed as UNESCO World Heritage Sites. Since then, the ancient fortifications on the Grünewald heights have also been included in the World Heritage buffer zone.
On 5 December 1996, the Chamber of Deputies approved two laws to establish a Museum of Modern Art (Musée d'Art Moderne) within the site and a Fortress Museum (Musée de la Forteresse) in the redoubt of Fort Thüngen.
The law of 25 April 2003 on the restoration and development of certain parts of the fortress of Luxembourg authorised work to be carried out on the Vauban Circuit and certain parts of the Thüngen redoubt, which was reconstructed using the designs from 1836/37. This reconstruction was carried out in accordance with the Venice International Charter for the Conservation and Restoration of Monuments and Sites from 1964. A broad masonry joint marks the separation between the redoubt's historic remains and its reconstructed parts.
The volume of the redoubt's formerly interposed earthen layers between the vaulted casemates and the gun platform on the roof has been replaced by an area of 800 m2 including an auditorium and a temporary exhibition space. The staircase from the second floor to the platform is a modern addition. The platform built from modern materials is largely in keeping with the original dimensions.