Rotonda

A massive circular temple from the early 4th century built under Emperor Galerius — scholars still debate whether it was a mausoleum or a pagan temple. Later it became a church with golden mosaics, then a mosque, which explains the minaret. Walls more than six metres thick have survived twenty centuries and earthquakes; inside, early Christian mosaics of saints remain. It sits by Egnatia Street next to the Arch of Galerius.