Starting at 2 Quai du Port, beside the Hôtel de Ville, you'll open the Explorial app, enter the 6-digit game code that you received by text and Viator chat message, and set out along the Vieux-Port. The tour is fully self-guided — no guide, no fixed start time, just your group and the city. The Hôtel de Ville anchors the first riddles — a baroque survivor of the old quarter, watching fishing boats give way to yachts for three centuries. Then the route rises through the Panier toward Sainte-Marie-Majeure, the striped neo-Byzantine cathedral big enough to hold 3,000 believers and several trivia questions. Fort Saint-Jean closes the loop where the city meets the sea, its ramparts now bridging to the bold MuCEM museum. Around two hours of salt air and steep lanes. Pastis and the final leaderboard await at the port.