Anwerp is in the Flanders region in Belgium, and is the diamond trading hub of the world. It is an easy drive away from Brussels. All tourist destinations in the city can be easily covered on foot.
The city center or the Grote Markt is a beautiful square with Flemish / Dutch architecture, cafes, fountain, sculptures, horse carts, and flags. It is walking distance close to the river. The Town Hall is the most imposing building in the Grote Markt and difficult to miss.
You could take in this view, preferably under the sun, with a beer in one of the cafes in the city center.
You can walk to the river or nearby churches from here, followed by a walk to the Diamond District.