Every January in the small Spanish town of San Bartolome de Pinares, daring locals ride their horses through bonfires in a five hundred-year-old festival known as Las Luminarias. The tradition is a nod to the patron saint of animals, Saint Anthony, and takes place every year on the eve of his feast day - January 16. The fire and smoke is believed to help purify the horses and protect them from disease in the coming year. The exact origin of the Las Luminarias, which dates back to the middle ages, is unknown, though it is thought to have began at a time when animals were contracting unexplained illnesses and dying in huge numbers.