The second most important arms museum in Europe, reflecting Liège's long history as a centre of arms manufacturing — most weapons were made in the factories of Herstal, just outside the city. The collection is housed in a neo-classical building constructed between 1775 and 1779.
During the French occupation the building served as the seat of the Prefect of the Département de l'Ourthe, and Napoleon Bonaparte stayed here twice. In 1858 it was purchased by arms manufacturer and collector Pierre Joseph Lemille, and after his death the city of Liège acquired it for the collection. More than 13,000 items are held in total, with a selection on permanent display — rewarding for both the specialist and the curious visitor.