Fort Thüngen is a historic fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

 in Luxembourg City, in southern Luxembourg

Luxembourg

Luxembourg , officially the Grand Duchy of Luxembourg , is a landlocked country in western Europe, bordered by Belgium, France, and Germany. It has two principal regions: the Oesling in the North as part of the Ardennes massif, and the Gutland in the south...

. It is sited in Dräi Eechelen Park, in the Kirchberg

Kirchberg, Luxembourg

Kirchberg or the Kirchberg is a quarter in north-eastern Luxembourg City, in southern Luxembourg. It consists of a plateau situated to the north-east of the city centre, Ville Haute....

 quarter

Quarters of Luxembourg City

The Quarters of Luxembourg City are the smallest administrative division for local government in Luxembourg City, the capital and largest city in the Grand Duchy of Luxembourg....

, in the north-east of the city. It is also colloquially known as Three Acorns in reference to the acorns that sit atop each of the three tower

Tower

A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....

s.

Most of the original fortress was demolished after the 1867 Treaty of London

Treaty of London, 1867

The Treaty of London , often called the Second Treaty of London after the 1839 Treaty, was an international treaty signed on 11 May 1867. Agreed in the aftermath of the Austro-Prussian War and the Luxembourg Crisis, it had wide-reaching consequences for Luxembourg and for relations between...

, which demanded the demolition of Luxembourg City's numerous fortifications. The three towers and the foundations of the rest of the fort were all that remained. During the 1990s, the site was reconstructed in its entirety, in parallel with the development of the site for the construction of the Mudam

Mudam

The Grand Duke Jean Museum of Modern Art , abbreviated to Mudam, is a museum of modern art in Luxembourg City, in southern Luxembourg. The museum stands on the site of the old Fort Thüngen, in the Kirchberg quarter, in the north-east of the city....

, Luxembourg's museum

Museum

A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...

 of modern art

Modern art

Modern art includes artistic works produced during the period extending roughly from the 1860s to the 1970s, and denotes the style and philosophy of the art produced during that era. The term is usually associated with art in which the traditions of the past have been thrown aside in a spirit of...

.