On 12 December 1531, Our Lady instructed Juan Diego to gather Castilian roses. He collected the roses in his cloak. This was miraculous in itself as the roses had bloomed despite the winter weather. 
When Juan Diego went to give the miraculous roses to the bishop, as he opened his cloak, the roses fell to the ground to reveal a miraculous image of the Virgin Mary on the fabric of his cloak. The intricate detail and rich cultural and historic symbolism of the image was remarkable.

The cloak (called a tilma) was made from plant fibres and therefore should have deteriorated within twenty years. Nevertheless, it still remains miraculously preserved. Furthermore, for the first 116 years, the image was displayed without any protection.

The vibrant image on the cloak has not faded over time and there is no evidence of brushstrokes. The colours pass through the threads as if they were part of the fabric. The pigment of the coloured fibres also are unknown in nature. 

In 1921, a bomb, hidden in a wreath of flowers, was placed on the altar below the image. Despite the detonation being felt 1km away and causing the candelabras to be thrown into the air and the bronze crucifix to be bent, the glass protecting the image did not break. 

The constellations made up of 46 stars on Our Lady’s mantle are astronomically accurate to the morning of December 12, 1531 (the date of the apparition). 

Recent technological developments have allowed for increased magnification of the image of Our Lady’s eyes and has uncovered human figures believed to be Juan Diego and those present when the image was first revealed.