A large public park, the Cinquantenaire Park (or "Parc du Cinquantenaire" as it is known in French) is dominated by buildings built for the 1880 National Exhibition which also celebrated fifty years of Belgian independence. The centerpiece of the park is a triumphal arch finished in 1905.
To the north of the arch is the Royal Military Museum. To the south are the Royal Museums for Art and History (these hold artifacts gathered from around the world), and AutoWorld, a vintage car museum with over 350 classic cars, one of the largest collections in Europe.
If you’re looking for an impressive place to lie under a tree the Cinquantenaire Park is especially lovely in the summer when it’s filled with locals making the most of the sunshine.
Also in summer the area surrounding the arch is turned into a drive-in cinema. There’s discounted tickets for people driving vintage cars and a lawn reserved for people on bicycle or foot.
If you want to wander through the park, the closest station is Schuman to the west. If you're heading straight to the museums then Merode to the west will get you there quicker.