Sant Antoni is a neighborhood in the Eixample district of Barcelona, Catalonia (Spain). Its non-official centre, the marketplace of the same name—designed by Antoni Rovira i Trias and built between 1872 and 1882—is one of the oldest and most popular in the city, especially with the secondhand book stalls that surround the building Sunday mornings. It is bordered by the neighbourhoods of the L'Antiga Esquerra de l'Eixample (on the other side of Gran Via de les Corts Catalanes), the Raval (on the other side of Ronda de Sant Antoni), and Poble Sec (on the other side of Avinguda del Paral·lel). The streets of Sant Antoni follow the grid pattern prevalent in all of Eixample, except for a central thoroughfare, the Avinguda de Mistral, built on the site of an important medieval road which lead out of Barcelona.