Ex-Convent of Tepoztlán (Museo de la Natividad) is just e. of the main plaza, off Av. Revolución 1910 next to the church. Built by Dominican friars, it was completed in 1588. Some walls of this massive structure are more than 6 feet thick. It has a crumbling beauty—much of the plaster has peeled away over time—and walls covered with beautiful murals. Upstairs is the small Historical Museum of Tepoztlán, with five rooms of interesting exhibits that depict the region's religious, ethnological and natural history. Information is in Spanish.
The church adjoining the monastery has twin spires, a barrel-vaulted interior and a walled atrium filled with aromatic eucalyptus trees. Religious paintings done by local artists also are on display. The mural at the entry gate is a portrait of the convent's history created entirely from dried beans, corn kernels and other grains.