The Convento de la Santa Cruz occupies a commanding position on a hill east of the historic centre, with views across the rooftops and out to the Sierras. The Franciscan monastery was founded in 1531 on the site of a decisive battle between Spanish and indigenous forces, and it became one of the most important missionary training centres in the Americas — the base from which Franciscans spread across northern Mexico and into what is now Texas, New Mexico, and California.
The monastery buildings are largely intact and can be visited on guided tours that take you through the cells, the refectory, the cloister garden, and the church. The legendary cross-thorn tree in the garden is the highlight for many visitors. During Emperor Maximilian's siege of Querétaro in 1867, the monastery served as the emperor's headquarters, and some of his personal effects remain on display. The views from the monastery terraces are the best in the city.