This gem is on the UNESCO World Heritage List. Built in 1745, the Sanctuary of Atotonilco contains a ceiling and six side chapels that are breathtaking, as well as an exceptional ensemble of frescoes and murals, by Miguel Antonio Martínez de Pocasangre. In 1802 Ignacio Allende was married in this church, and Father Hidalgo was arrested here in 1810 in the course of his march on San Miguel. Today it is a pilgrimage site.