Cardiff packs a surprising range of sights into a compact city centre, from Roman foundations and Norman keeps to world-class galleries and a transformed waterfront. Cardiff Castle is the obvious starting point, but the National Museum Cardiff holds one of the finest Impressionist collections in Britain and deserves a full half-day. Down at Cardiff Bay, the Wales Millennium Centre and the Senedd face each other across the waterfront plaza. The Victorian arcades running through the city centre are a joy to wander.