Cortés’ imposing medieval-style fortress stands opposite the southeast end of the Plaza de Armas. This two-story stone palace was built in 1535 on the base of the city pyramid that Cortés destroyed after taking Cuauhnáhuac. The base is still visible from various points on the ground floor. An earthquake in 2017 damaged the building, and at the time of writing the Palacio remains closed for years-long repairs. Only a tiny exhibition (free) remains open, with relics from pre-Hispanic cultures.

　　The palace houses the excellent Museo Regional Cuauhnáhuac, which has two floors of exhibits highlighting Mexican cultures and history.

　　On the upstairs balcony is a fascinating mural by Diego Rivera, Historia del Estado de Morelos. The mural was commissioned in the mid-1920s by Dwight Morrow, the US ambassador to Mexico. Flowing from right to left, scenes from the conquest through to the 1910 Revolution emphasize the cruelty, oppression and violence that have characterized Mexican history.

　　While upstairs covers events from the Spanish conquest to the present, the ground floor exhibits focus on pre-Hispanic cultures, including the local Tlahuica and their relationship with the Aztec empire. Most labeling is in Spanish only, with a few well-translated exceptions.

　　Cortés resided here until he turned tail for Spain in 1541. The palace remained with Cortés’ family for most of the next century, but by the 18th century it was being used as a prison. During the Porfirio Díaz era it became government offices.