There are many things to see and do with your free time in and around Brussels, like:
Rue Royale: Several museums are found in this area, especially the Musée Royaux des Beaux Art, the Musée d’Art Ancien, and the Musée d’Art Moderne. The King’s working palace is open to the public during August and early September. You can also learn about the history of Belgium and visit the remnants of the Emporer Charles V’s palace at the BELvue museum.
Cinquantenaire: A 90-acre park with the Triumphal Arch commemorating Belgian independence. Three museums are here: Royal Museum of Art and History, Autoworld, and the Military History Museum with an impressive collection of artifacts from every army that has ever been in Belgium.
Sablon: The Grand Sablon is a lovely square and center of an antique market on weekends. It’s fun to browse the market or have coffee in one of the old craftsmen houses that surround the square. The Petit Sablon is an attractive park surrounded by 48 statues representing the different Medieval guilds.
Les Marolles: This area is the old working class quarter. The Palais de Justice (law courts) dominates the skyline. The Porte de Hal is the only part of the 14th century wall to remain standing.
Art Nouveau: Belgium is world renowned for its Art Nouveau architecture and one of its founders was Belgian. His home, the Victor Horta House, is a museum on rue Américain and worth a visit.
Waterloo: The Butte de Lion is an artificial knoll which commemorates Wellington's victory at Waterloo. Climbing the 226 steps offers a view of the plain where Napoleon was defeated. The Visitors Center has a museum and movie that gives background about the battle.
Around the Grand Place: In the center of town is Brussels' market place with its beautiful Flemish town hall, guild halls and Maison du Roi. Near the Grand Place is the legendary Manneken Pis. This area also offers several lace and tapestry shops. There’s a flower market here on Sundays.
Anderlecht: It doesn’t get a lot of foreign visitors, but the sixteenth century humanist Erasmus lived here. If you want to see what a sixteenth century home looked like, learn about the enlightenment and see some rare historical artifacts from the period, visit the Erasmus House.
Bruparck is an entertainment complex with four separate facilities: MiniEurope (scaled down European cities), Oceadium (water park), the Village (Belgium of the 30's) and Kinepolis (27-theatre complex).
Lakes and Forests: The Bois de la Cambre, the largest park in Brussels, adjoins the Forêt de Soignes, a beech forest which stretches to Waterloo. The Bois is great for picnics, walks, jogging, etc. Finally, don’t forget the Park at Tervuren where you will also find the Museum of Central Africa filled with artifacts from Belgium’s colonial days in the Congo.
Laeken: The Royal Palace is the home of the royal family. Although the palace itself isn't open for visits, the Royal Greenhouse opens in May to the public. King Leopold II bought two oriental monuments from the Paris Exhibition in 1900, a Japanese Tower and Chinese Pavilion. The Atomium, built for the 1858 World Fair represents a molecule of iron crystal--335 feet high!
Brussels is an amazing place to walk among historic architecture and learn about important influences.