Athens gets the tourists, and Thessaloniki gets the Greeks. Ask people in Athens where they'd rather go out, eat or study, and a surprising number will say Thessaloniki, the country's second city, on a bay in the north. It was founded in 315 BC and named after Alexander the Great's half-sister, and for most of the 2,300 years since it was the second city of somebody's empire: a Roman capital under Galerius, the second city of Byzantium, then an Ottoman port where Greeks, Turks and Sephardic Jews lived side by side. Jews were the largest community here for four centuries, and people called the city the Jerusalem of the Balkans. It only became part of Greece in 1912.
All of that is stacked on top of itself. Roman arches stand at bus stops, Byzantine churches are wedged between apartment blocks, and the new metro had to be built around a Byzantine main street that is still on display in the station. And on top of the history is a city that lives outdoors: bougatsa at dawn, coffee for hours, a walk along the sea at sunset and meze and tsipouro until late. Five days is the right amount of time to enjoy both.
The plan keeps each day in one part of the city. Day one is the center and the waterfront, day two Roman and Byzantine Thessaloniki, day three Hagios Demetrios and the old upper town, day four a trip to the royal tombs of Vergina, and day five the museums, the Jewish city and a farewell dinner by the sea. For more time, the best trips out of town come after day five. Thessaloniki is also a good first taste of Greece away from the islands, the Greece of city life rather than beaches.