The Virgin of Guadalupe.
From Wikipedia: In December 1531, Juan Diego saw a vision of a young girl of fifteen or sixteen, surrounded by light, on the slopes of the Hill of Tepeyac. In his native language she asked. From her words, Juan Diego recognized her as the Virgin Mary. Diego told his story to the bishop who instructed him to return and ask the Lady for a miraculous sign to prove her claim. The Virgin told Juan Diego to gather some flowers from the top of Tepeyac Hill. It was winter and very late in the season for any flowers to bloom, but on the hilltop (which was usually barren), Diego found Castillian roses, and the Virgin herself arranged them in his tilma (peasant cloak). When Juan Diego opened the cloak before the bishop on December 12, the flowers fell to the floor, and in their place was the Virgin of Guadalupe, miraculously imprinted on the fabric.
A very small parade came down the street in front of the marina just at sunset. The Virgin of Guadalupe is the patron saint of Mexico and her images are everywhere; in homes, on buses, even on bathroom air fresheners. This is one of the most important saints' days in Mexico.