Starting at 71 Mun Mueang Road in the old city, you'll open the Explorial app, enter the 6-digit game code that you received by text and Viator chat message, and slip inside the moated square. The tour is fully self-guided — no guide, no fixed start time, just your group and the city. The Three Kings Monument gathers the city's founders in bronze — Mengrai and his allies who planned Chiang Mai in 1296. Riddles consult the royal trio. Wat Inthakhin Sadue Muang follows, the small temple guarding the city pillar where Chiang Mai's spirit is said to reside. Trivia treads respectfully. Then the Tha Phae Gate opens the old wall's eastern face, its brick arch the backdrop for markets, festivals and several thousand photos a day — one of them yours. Around two hours among temples and tamarind shade. The leaderboard crowns the winner; mango sticky rice crowns everyone else.