Thessaloniki has the odd distinction of being a Roman city, a Byzantine city, an Ottoman city and a Greek city, all at once, and the churches that UNESCO listed in 1988 tell the earliest part of the story. The Paleochristian and Byzantine monuments include the Rotunda, a huge round brick building put up around AD 300 as a mausoleum for the emperor Galerius, and later converted into a church. Its walls are about six metres thick, and it stands beside the remains of Galerius's palace and triumphal arch. A minaret from the Ottoman period still rises beside it.
The other great monuments are the basilica of Hagios Demetrios, dedicated to the city's patron saint, who is said to have been martyred here in the early fourth century, and the church of Hagia Sophia, with its mosaic of the Ascension in the dome. The early Christian basilica of Acheiropoietos, with its simple columned nave, is among the oldest churches in Greece. In 1917 a huge fire destroyed much of the city, including Hagios Demetrios, which was rebuilt afterwards, and visitors can still see the crypt where the saint is said to have been held.
Ágios Pávlos lies just above the old centre, in the quieter upper town where the streets climb toward the Byzantine walls and the wooded slopes behind. The upper town, called Ano Poli, survived the fire and has retained its crooked lanes, Ottoman houses and little churches. From the walls you can look down over the red roofs of the city to the sea and, on a clear day, to Mount Olympus floating on the far horizon.
Riding in Thessaloniki is a challenge: the traffic is fast and unpredictable, the roads are steep and cobbled in the upper town, and parking is scarce. It makes sense to park near the edge and walk. Beyond the city, the road along the coast toward Halkidiki is a pleasant run, with sea views and light traffic outside high summer.
Thessaloniki is the second city of Greece, with plenty of fuel and food. Try a bougatsa, a pastry filled with custard or cheese, for breakfast, and a koulouri, a sesame ring, from a street seller.