Unitarist lawyers and clerics declared Argentina’s independence from Spain on July 9, 1816, in this late-colonial mansion. Portraits of the signatories line the walls of the original room. There’s plenty of information in Spanish on the lead-up to this seismic event, and English guided tours (free) are available. There’s a sound-and-light show nightly except Thursdays; entry is AR$10/5 per adult/child. Get tickets at the tourist office.
Alongside the building are areas with handicrafts stalls and stands selling traditional foods.