The Museo Regional de Rancagua is the city's principal museum, occupying a pair of restored colonial houses just north of the Plaza de los Héroes. The collection covers the archaeology of the central valley, colonial life, and — at length — the 1814 battle that defined the city's national role.
The setting is half the point. Walking from one whitewashed room to another, with the inner patios open to the sky and the original 18th-century roof beams overhead, gives a better sense of late-colonial Chilean domestic life than anything in Santiago. Entry is free. Closed Mondays.