There's that much to see, if you're there for a day I'd consider taking the 90-minute walk in the Eyewitness Guide (http://www.amazon.co.uk/Brussels-Bru...8292910&sr=8-1), a short (30-min) tour along the canal (which isn't especially educational, but is a wonderful way to see some of the most impressive buildings) and spend the rest of the day ambling around.

A day isn't very long here - although it's very small, there are several museums and plenty of streets to walk along. And don't miss the Moules!