Thessaloniki is best discovered by walking along the water. The terminal is about 1.5 km from the centre, and a quarter-hour stroll along the waterfront is enough to reach Aristotelous Square, the beating heart of Greece's second-largest city. Along the way, cafés spill onto the sidewalks, students put the world to rights and vendors of koulouri, sesame bread rings, call out to passers-by. Byzantine, Ottoman, Jewish, Greek: the city has been all of these at once, and every neighbourhood still bears a trace.

The White Tower, sentinel of the gulf

You can't miss it: the White Tower punctuates the promenade like an exclamation mark. This 15th-century fortified rotunda, a former Ottoman prison, now houses a museum that unfolds the city's history floor by floor. The spiral climb leads to a circular terrace from which the eye takes in the Thermaic Gulf and, on clear days, the silhouette of Mount Olympus across the water. It's hard to find a better vantage point for taking the measure of the place.

Galerius, the Rotunda and golden mosaics

A few streets higher, the Arch of Galerius spans the old Roman road, its reliefs recounting the emperor's campaigns. Just behind it, the Rotunda, a colossal 4th-century circular building, has served in turn as a mausoleum, a church and a mosque; its golden mosaics are among the oldest in Christian art. Everything can be visited on foot, each monument a few streets from the last. The city's Byzantine churches are on the UNESCO World Heritage List, and the Basilica of Agios Dimitrios, dedicated to the city's patron saint, hides in its crypt the remains of the baths where he was imprisoned.

Ano Poli, the upper town

To experience another Thessaloniki, a taxi or bus climbs to Ano Poli, the old upper quarter spared by the great fire of 1917. Ottoman houses with overhanging upper floors cling to the slopes, cobbled lanes wind between gardens, and Byzantine walls crown it all. From the heights of the ramparts, the whole city spreads out to the sea, a panorama that alone justifies the detour. Walking back down with no set route holds the best surprises. Along the way, icon painters' workshops and neighbourhood cafés remind you that these slopes are still lived in, far from any staging.

Markets, bougatsa and café culture

Back toward the centre, the Modiano market hall and Kapani market concentrate the scents of the Levant: olives, spices, fish on ice and mountains of cheese. Vendors happily offer an olive or a cube of feta to taste, a sales pitch as old as the market halls. This is the time to try bougatsa, a pastry filled with cream or cheese that Thessalonians enjoy at any hour. The city vies with Athens for the title of the country's culinary capital, and its tavernas and pastry shops make a strong case. A café frappé on a terrace seals the deal.

The promenade of the umbrellas

Weather permitting, the Nea Paralia, a long redesigned esplanade stretching east, deserves a final stroll. Residents jog, cycle and walk strollers and grandparents there, facing the sea. Zongolopoulos's sculpture "Umbrellas", a soaring flight of steel rods and canopies, has become the area's modern emblem; at sunset, photographers jostle politely for a spot.

Heading back to the ship along the same waterfront, you realize how far you've come in a few hours: Rome, Byzantium and the Ottoman Empire crossed between two coffees. Thessaloniki doesn't freeze its history in display cases. It lives it, loudly and generously, and leaves travellers with a very clear desire to return when the tavernas light their lamps.