Plaza Dorrego is the main square in San Telmo and where the action happens. Every Sunday, the plaza is taken over by an antique market with 300 stalls offering a mix of antiques, vinyl records, and glass soda bottles. At the end of the afternoon on Sunday, a dance floor turns the plaza into a milonga (outdoor tango dance hall). This is a great spot to catch authentic tango for free.

The length of Defensa Street is also a market on Sundays but instead of antiques it is more artisans selling their crafts. It is the best way to spend a Sunday in Buenos AIres.

On the other 7 days of the week, Plaza Dorrego is a great spot for a meal or a beer at the restaurants with tables out on the plaza. Tango performers dance for the diners (tips expected, have cash).