Leo, the first U.S.-born pope, was elected on May 8 by the world's cardinals to replace the late Pope Francis. Pope Leo celebrated the largest event yet of his nearly three-month tenure on Sunday, encouraging a crowd of more than a million Catholic young people gathered in a field on the outskirts of Rome to spread their faith.

Hundreds of thousands of young faithful feted Pope Leo XIV like a rock star Saturday at an open-air prayer vigil outside Rome, after the head of the Catholic Church made a dramatic entrance by helicopter.