The pedestrian spine of old Rouen, a straight cobbled street running from the cathedral past the great clock to the Place du Vieux-Marché. The street is lined with half-timbered houses, many leaning slightly out over the pavement, and is the busiest stretch in town at any hour of any day.
Most of the shops are chains, but the architecture is the point. Walk it slowly; pop down the side alleys, especially the Rue Saint-Romain behind the cathedral, where the canopies are even lower and the houses lean even further.