Why go
Start with a contrast rather than a checklist. The Barri Gòtic shows the older street fabric; Passeig de Gràcia links Casa Batlló and Casa Milà; Sagrada Família and Sant Pau reward a closer look at two distinct modernista approaches. The contrast makes the city easier to understand.
The full story
The Barri Gòtic preserves a dense street pattern around the old centre, with medieval buildings and traces of the Roman city. The Eixample opens into wider avenues and regular blocks. There, modernisme appears in very different forms, from the stone movement of Gaudí’s Casa Milà to the façades along Passeig de Gràcia. Sagrada Família is a larger, still developing church project; Sant Pau shows how Lluís Domènech i Montaner applied modernista design to a hospital complex. On Montjuïc, the 1929 exposition and the later Olympic landscape add other chapters. Near Glòries, the renewed park and Torre Glòries signal a much newer phase of urban change. These areas are too far apart for a satisfying single sweep on foot. Choose one architectural thread or pair nearby sites, and leave room to notice the streets between them.