How Do Fire-Walking Rituals Work?

Dimitri Zigalata met a man named Ali Handro in the Spanish village of San Pedro Manrique. People hold him in very high esteem in that village because he's one of the oldest fireworkers. He has been doing this ritual for many decades. On the summer solstice, every June, people start gathering in the central square. They engage in all kinds of processions and other celebrations throughout the day. In the evening, they all join hands and they form this human chain. And once everybody takes their place at exactly midnight, people start taking off their shoes and they face a large pit of coals.