The Palacio de Cortés dominates the east side of the Zócalo in Cuernavaca and is the oldest preserved colonial civil building in the Americas. Hernán Cortés began construction in 1522 — barely a year after the fall of Tenochtitlan — on the foundations of a ceremonial platform belonging to the city that preceded Cuernavaca. The thick stone walls and corner towers give it the look of a fortress, which in the turbulent early years of the colony it sometimes functioned as one.
Today the building houses the Museo Regional Cuauhnáhuac, which traces the history of the region from pre-Hispanic times through independence. The permanent collection is well-organised and includes Aztec stone carvings, colonial-era religious art, and exhibits on the Zapatista uprising and land reform. The panoramic view of Popocatépetl from the upper terrace, with Rivera's mural as backdrop, is one of the best in the city.