Leo canonized Carlo Acutis, who died in 2006, during an open-air Mass in St. Peter’s Square before an estimated 80,000 people, many of them millennials and couples with young children.

An online influencer, who was just 15 years old when he died, is the Catholic Church's newest saint. Pope Leo XIV led a canonization ceremony over the weekend for Carlo Acutis, the first millennial saint.