The Plaza de los Héroes is the heart of colonial Rancagua and the site of the city's defining moment. The square is dominated by an equestrian statue of Bernardo O'Higgins and ringed by the cathedral, the municipal building, and the old administrative buildings of the colonial period.
Walk it in the late afternoon. Locals fill the benches and a few cafés set out tables on the surrounding streets. The plaza is the obvious starting point for any visit and gives the city its sense of historic weight — small as Rancagua is, this is where Chile's independence movement nearly died and from which it eventually rose.