Thessaloniki never demolishes its past; it stacks it. A Roman emperor's triumphal arch, a rotunda that has been temple, church and mosque, Byzantine cathedrals full of gold, and a whitewashed Ottoman tower that was once an execution ground all share the same street grid. This self-guided walking tour traces that layered spine through the heart of the city. Everything runs from your phone. You get a clear map of all 10 stops, simple directions through Google Maps, and a short audio story with an interactive quiz at each location. The route runs from the White Tower on the waterfront up through the Arch and Rotonda of Galerius, Hagia Sophia, Aristotelous Square and the Ladadika quarter, to the Roman Forum and the great basilica of Agios Dimitrios. Start anytime, pause whenever you like, and explore freely. No groups, no schedules. Audio and text available in 7 languages. And it comes with a free eSIM, redeemable once per account, so your map, directions and audio work from the moment you arrive, with no roaming charges.