Fort Leopold was built between 1841 and 1845. It is dug into the southern slope of the Lazarijberg (Lazar House Hill), about 400 metres outside the city. Thanks to its remarkable tower-shaped construction, it offers the possibility to fire in all directions. The fort had a dual purpose. On the one hand, preventing the enemy from occupying the plateau located directly in front, an ideal spot to take a shot at the city. And on the other hand, to protect the northern city front line by bombarding the enemy from the rear. Access to the fort was protected by means of a wide and deep dry moat. There are two earthen battle platforms on top of the fort and two brick batteries in the direction of the city.
During the First World War, the Germans used the fort for storage and for shorter periods, as sleeping quarters. After the war, a Frenchman started a mushroom farm and an orchard was planted on the surrounding hillside. During the Second World War, the occupiers used it for storage once again. Today Fort Leopold is empty.