Starting at the Käfigturm on Marktgasse — the old prison tower — you'll open the Explorial app, enter the 6-digit game code that you received by text and Viator chat message, and follow the arcades into the UNESCO old town. The tour is fully self-guided — no guide, no fixed start time, just your group and the city. The Bundeshaus commands its terrace above the Aare, green dome and all. Riddles poke gently at Swiss democracy — the fountain plaza out front counts 26 jets, one per canton. At the Zytglogge, trivia waits for the hour: jesters, roosters and bears perform their 500-year-old routine on the astronomical clock that young Einstein passed daily. Then the Rathaus closes the circuit, the Gothic hall where Bern's councils have argued since 1406. Around two hours under six kilometres of arcades. The final ranking is announced — calmly, this is Bern.