San Telmo is Buenos Aires’ oldest residential neighborhood and its Sunday street fair — the Feria de San Telmo — is one of the most atmospheric open-air markets in South America. Every week, Calle Defensa transforms into a kilometer-long river of antique dealers, vintage clothing vendors, leather artisans, mate gourd sellers, and street musicians, stretching from Plaza de Mayo all the way to Parque Lezama. The cobblestone streets echo with the melancholy strains of bandoneons as tango dancers perform impromptu shows at intersections, drawing circles of mesmerized spectators. The permanent indoor Mercado de San Telmo, housed in a beautiful 1897 iron-and-glass structure, is a foodie paradise where you can graze on fresh empanadas, artisan cheeses, craft vermouth, and some of the best choripan sandwiches in the city.

Beyond the markets, San Telmo itself is a neighborhood of crumbling grandeur, with ornate Italianate facades, hidden courtyards, and dimly lit milongas where locals dance tango until the early hours. The warren of antique shops along Defensa and surrounding streets is a treasure hunter’s dream, stocked with everything from art deco furniture and vintage soda siphons to century-old tango sheet music and silverwork from the pampas.

Pro tip: Skip the overpriced parrillas on the main drag and duck into the Mercado de San Telmo for lunch — the small counter-service stalls inside offer incredible quality at a fraction of restaurant prices. For the Sunday fair, arrive before 11:00 AM to browse comfortably, as the crowds become very dense by early afternoon.