Bari Vecchia is the old city, a dense headland of narrow alleys, medieval churches, and whitewashed houses squeezed between the old port and the fishing harbour. It is genuinely still a neighbourhood as much as a tourist attraction — elderly women sit in doorways making pasta, children kick footballs against chapel walls, and the smells of frying fish and baking bread come through open windows.
The main sights — the Basilica di San Nicola, the Swabian Castle, the Cathedral of San Sabino — are all within a short walk of each other. The alleys are deliberately confusing, a deliberate defence design from the days when the city needed to disorient attackers. Getting lost is the point: the occasional piazza or unexpected sea view through a gap in the walls provides its own reward. The old town is best explored in the morning before the crowds arrive.