Starting at the Spitalbastei, the mighty southern bastion, you'll open the Explorial app, enter the 6-digit game code that you received by text and Viator chat message, and pass through the walls into the old town. The tour is fully self-guided — no guide, no fixed start time, just your group and the city. The Plönlein soon appears — the tilted yellow house between two tower gates that launched a million postcards and, allegedly, a Disney sketch or two. The photo task is mandatory by moral law. At the Klingentorbastei, riddles patrol the northern defences, where wall, tower and waterworks combined into one clever fortress corner. Then the Stadtkirche St. Jakob delivers the finale: Tilman Riemenschneider's Holy Blood altar, carved so finely it seems to breathe. Around two hours inside the walls — after dark, the night watchman takes over. The leaderboard names the truest Rothenburger.