VATICAN CITY (AP) — The Vatican has revised how it evaluates purported supernatural events, such as reported visions of the Virgin Mary, to guard against hoaxes and account for news going viral.

Previous approved apparitions have turned these sites into major pilgrimage destinations, drawing millions of people to them each year:

— Our Lady of Guadalupe, Mexico: An Indigenous Mexican man named Juan Diego reported several apparitions of the Virgin Mary in 1531. For believers, the image of the Virgin that hangs in the basilica is a miracle itself, made when Juan Diego carried flowers in his cloak after receiving one of the visions, and upon opening it, found that the cloak displayed a detailed, colorful image of the Virgin.

— Lourdes, France: July 16 marks the anniversary of purported visions of Mary in 1858 by a young girl, Bernadette Soubirous, and the discovery of allegedly healing spring waters in southern France near the Pyrenees.