Once a year in mid-June, devils run wild in the Spanish village of Castrillo de Murcia.

A blend of Catholic and pagan rituals meant to represent the triumph of good over evil, the festival of El Colacho dates back to the 1620s and takes place on the Sunday after the Feast of Corpus Christi. Its origins are unclear, but some historians believe it may have started as a fertility ritual.

During the festival, red and yellow-masked “devils” run through the streets hurling insults at villagers and whipping them with a horsetail attached to a stick. When drums announce the arrival of the black-clad atabalero, pious men who who have come to drive out evil, el salto del Colacho—the flight of the devil—begins.

In a heart-stopping display, babies born during the previous year are laid on mattresses in the street while the costumed men leap over them. A baptism of sorts, it is believed that the devil absorbs the sins of the babies, and affords them protection from disease and misfortune. Spectators lining the streets will also berate Colacho in order to ward off their own bad luck for the upcoming year. Afterwards, the babies are sprinkled with rose petals and promptly reclaimed by their parents.

Traditionally the festival only included babies from the local village, but in recent years people from around the world have traveled to northern Spain to participate. To date there have been no reports of injuries, however the practice remains a subject of debate within the Catholic Church.

According to en.wikipedia and nationalgeographic.com