Shortly after the Spanish conquest of the Aztecs, a portrait of a dark-skinned lady, known as the Virgin of Guadalupe, appeared on the coarse, cactus-fibre cloak of an Indian peasant. Today, 450 years later, this painting hangs behind bullet-proof glass in Mexico's largest cathedral, where it is revered as a living miracle. Earlier this year a team of American scientists, formerly assembled to investigate the Shroud of Turin, were given permission to conduct tests on the Virgin of Guadalupe. Everyman reports on the remarkable history of Mexico's national icon, on the scientists' tests, and on their controversial findings.