[3] In 1875, the architect Gédéon Bordiau made a proposal to build on this site, part of the so-called "Linthout" plains, the former military exercise ground of the Garde Civique outside of Brussels' city centre.

Work resumed the following year under the direction of the French architect Charles Girault and was completed with a new patron, King Leopold II.

[3] Five years later, at the Brussels International Exposition of 1910, a section on military history was presented to the public on the same premises, and was met with great success.

Given the population's enthusiasm, the authorities decided to create a military museum within the international context of extreme tension that led to the Great War.

It is established in the curved galleries of the northern portion of the hemicycle, as well as in the metallic halls located to the west and south of the interior garden.

After 1945, the museum appropriated the entire pavilion; a section dedicated to Leopold III and World War II is set up there, inaugurated on 10 May 1955 by King Baudouin.

Completed for the 1880 exhibition, like its southern counterpart, destroyed by fire in 1946 (and since rebuilt), the North Hall is the oldest building in the complex.

The medieval collection presents an overview of the period's offensive and defensive armament, and consists of an extensive display of weapons, shields, and banners, from the simple coat of mail to the full armour.

The north wing, built by Gédéon Bordiau, has been occupied by the Aviation Hall since 1972, when the Air and Space gallery was inaugurated.

[citation needed] The collection includes various types of aircraft, both military and civilian, some dating back to the early 20th century.

In one of the open-air courtyards, several ships of the Belgian Navy are exhibited, among them a P903 Meuse patrol boat, as well as the yacht used by King Baudouin and Queen Fabiola.