Sant Antoni is the corner of the Eixample that spent a decade behind hoardings and came out the most talked-about quarter in the city. The market is the anchor; everything else is the neighbourhood that grew up around its long closure.
Start at the Mercat de Sant Antoni — Rovira i Trias's great iron shed of 1882, finally reopened, with a slice of the medieval wall on display in the basement where the builders found it. Come on a Sunday: the mercat dominical takes over the surrounding streets with books, coins and vinyl, and it's the whole reason to time the walk this way.
From there, cross the new superilla, the superblock where the cars were evicted and the benches moved in, and drop down to Carrer del Parlament. This is the vermut strip — order one, sweet and red with a soda siphon, the way the city does its Sunday noon. Walk west to the rougher Calàbria edge to see how new the polish is, then south toward Poble Sec and the metro.
