Boulogne's hilltop Upper City is an island of centuries-old buildings and cobblestone streets. You can walk all the way around this 'Fortified City' atop the ancient stone walls – look for signs for the Promenade des Remparts.
Highlights here include the Basilique Notre Dame, the Château-Musée, the neoclassical Hôtel Desandrouin and the 18th-century Hôtel de Ville with a medieval belfry.
