Feast of Our Lady of Guadalupe - Dec 12

Photograph of actual image, preserved in the Basica on Tepeyac Hill.

On December 9, 1531, Nahuan Mexican named Juan Diego beheld a vision of the Virgin Mary on Tepeyac Hill. The Virgin beseeched him, in his native language, to build a Church on the hill. Juan Diego rushed to the bishop’s residence, but it took three days for him to persuade the kindly but understandably skeptical bishop that the apparition was genuine. Juan Diego relayed to Mary the bishop’s request for a sign, and on December 12, the Virgin bade Juan Diego to gather Castilian roses (which were not indigenous to Tepeyac and couldn’t have grown there in winter, anyway) from the hill. Juan Diego found the roses and, when he released them from his tilma (cloak) before the bishop’s startled eyes, they both beheld the now-famous image of Guadalupe divinely imprinted on the fabric.
  The Feast Day of Our Lady of Guadalupe is the biggest day of the year for Mexicans and many across the continent.

(Adapted from the following...
http://anexamen.wordpress.com/2009/12/27/peregrinajes-y-posadas-2/)