The underground military complex is excavated in a marlstone hill on three levels. The ground plan measures 750m by 950m and the fort has a network of corridors of more than 5km. In 1940, the total surface area of the military-owned land extended to 75ha.
On the east side the fort is bordered by the Albert Canal and a near-vertical cliff face with a height of 60m. To the northwest the fort is protected by the river Jeker and by a wet moat which also allowed the land in front of the entrance to the fort to be flooded. On the south side a dry anti-tank moat with 4m tall concrete walls was dug. Barbed wire entanglements and anti-tank obstacles completed the ground defense.
A total of 17 bunkers equipped with the most modern weapons gave this military complex its reputation as amongst the strongest in Europe.
The role of the fort was to guard the bridges over the Meuse and the Albert Canal in the region of Visé, Maastricht and Lanaken and to prevent the German army from entering Belgium via this route.