Fort Thüngen
Three Acorns (Trois Glands in French)

A historic fortress built as a part of the city’s defences in the 18th century.

In order to strengthen the city's defences, Fort Thüngen was constructed between 1732 and 1733. Vauban, a French military engineer, designed it, and the Austrian army built it. The location of the fort was formerly occupied by a castle that was demolished in the 18th century.

General Baron von Thüngen, who oversaw the Austrian army at the time the fort was being built, is the inspiration behind the name Fort Thüngen. Due to the towers' acorn-like design atop a stem, the fort was also known as the Three Acorns. Four primary structures make up the stronghold, and they are joined by walkways and tunnels below ground. TThe Main Building, which is the largest and most noticeable building, has a central courtyard and a number of military-related facilities, including barracks, storage areas, and command centres. In the 19th century, the Capellen Building served as a prison; today, it is home to a museum that examines the fortress's history as well as the military history of Luxembourg.

During World War II, the fort was heavily damaged by German bombs, and it remained in a state of disrepair until the 1990s. Nazi art plundered during World War II was kept in the castle, including pieces by well-known artists like Rembrandt and Vermeer. The fort was restored and turned into a cultural centre by the Luxembourg government in the 1990s. The renowned glass pyramid of the Louvre Museum in Paris was designed by architect Ieoh Ming Pei, who oversaw the restoration project.