Vieux-Montréal is the one stretch of North America that does a convincing impression of an old European port, and the trick is to walk the lanes between the set pieces rather than tick the set pieces off. Under three kilometres, best early, before the calèches and the cruise crowds fill the cobbles.
Start in Place d'Armes with the basilica in front of you, and go in — Notre-Dame's deep-blue vault is worth the ticket and worth arriving at opening for. From there drop down to Place Jacques-Cartier, the sloping square of terrasses with the Nelson Column at the top and the Hôtel de Ville's turrets across the way. You don't have to stop at the city hall, but look up at the balcony de Gaulle made famous.
Then the quiet half: Rue Saint-Paul, the oldest street in the city, narrow and stone-walled, running west toward the silver dome of Marché Bonsecours. End on Rue Saint-Jacques, the old bank canyon, columns stacked storey on storey from when this was Canada's money. Champ-de-Mars and the metro are minutes away.