The Museo Histórico Nacional occupies the Real Casa de Correos — the old colonial post office on the Plaza de Armas, a grand neoclassical building completed in 1882. The collection traces Chilean history from pre-Columbian times through the 20th century, with particular strength in the colonial period and the wars of independence. The room covering the Pinochet era is handled carefully and without the circumspection that often creeps into officially funded institutions dealing with recent trauma.
The building itself is worth the visit: the central atrium is a magnificent space, and the surrounding rooms retain their 19th-century architectural character. Free admission most days; the museum is currently being expanded. Open Tuesday to Sunday, 10 a.m. to 6 p.m.