Cassander of Macedonia founded a city at the foot of Mount Chortiatos in 315 B.C and named it after his wife, Thessaloniki, the sister of Alexander the Great. The city grew rapidly until it became the capital of Roman Macedonia. Today, it has some of the best examples of Byzantine art and architecture. Numerous churches contain mosaics, frescos and icons. Visit the White Tower a 15th-century Venetian fortification.