The National Museum of Military History is mainly devoted to the Battle of the Bulge of World War II. At first glance the building has the appearance of a disorganized warehouse, but the reality is the museum is quite large with many, many things to see. The exhibits are filled with collections of weapons, military equipment, and interesting pieces dating back to World War II. The museum looks a little aged, but it's still quite interesting for people interested in WWII and the peacekeeping efforts that followed. There are easily thousands of artifacts from the Battle of the Bulge. You can rent a narrative audioguide for 2.5 euros. Entrance to the museum is five euros.