If the day's weather forecast is grim, why not spend the day at Landesmuseum? You'll be fascinated by just how much you can discover about the past here.
When you've spent some time at this collection of historical artifacts in Braunschweig City Center, why not check out Braunschweig Farmers Market, Brunswick Cathedral, and Schloss Arkaden Braunschweig? They're not too far from Landesmuseum and also popular with tourists.