The Parte Vieja — the old town — is the gastronomic heart of San Sebastián and the first place every visitor should go. The grid of narrow streets between Monte Urgull and the harbour contains the highest concentration of pintxo bars anywhere in the world, along with the market, the basilica, the San Telmo Museum, and the medieval street plan that survived the British bombardment and burning of the city in 1813 (the current old town is mostly 19th-century reconstruction, but the street pattern is older).
The key streets are Calle Mayor, Calle 31 de Agosto, and Calle Fermín Calbetón. From about 7pm onwards the bars fill up; the pintxo crawl — moving from bar to bar, eating two or three small snacks at each — is the standard evening ritual. Prices are low and the quality is extraordinary: this is not tourist food but the daily reality of how Basques eat.