The Arch of Galerius has plenty of details showing the power of the emperor. It has plenty of marble sculptures on its surface providing details of a victory over the Persians. Right now, it is on a pedestrian area of a Thessaloniki main road, and pedestrians can walk underneath its partially-destroyed yet still majestic structure.
About one hundred meters to the north is the Church of the Rotunda. It is thought that its original function was a mausoleum, or a temple, yet archaeologists seem to not agree on which god this temple should have belonged to. It then functioned as a Greek Orthodox Church, yet when the Ottomans came, it was converted into a mosque, hence there is a minaret that was attached to it, standing until now. In 1912, when Greece recaptured this area, the mosque was reconverted into a church, and nowadays it is a historical monument.
When I visited, the interior was under construction, as shown by the photos above. Nevertheless, it was accessible to the public, and I definitely recommend a visit to this place if you are in the city.
