You may spot Cathedral of Saint Gregory Palamas in the skyline before you actually find this amazing religious building. Pop inside if the doors are open or just appreciate the facade from the street.
When you've finished up at this principal church in Thessaloniki City Centre, why not make your way to Aristotelous Square, White Tower of Thessaloniki, and Church of Saint Demetrius? They're close to Cathedral of Saint Gregory Palamas and also popular with tourists.