By Joshua McElwee

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.

Amid shouts of “Viva il Papa” (Long live the Pope) from young people dressed in colourful t-shirts and waving national flags at the Tor Vergata field, Leo led a Mass that capped a special week of events meant to energise Catholic youth.

“Dear young people … spread your enthusiasm and the witness of your faith to everyone you meet,” the pope said during his sermon for the event.

Leo also lamented the ongoing wars in Gaza and Ukraine in an appeal at the end of the Mass, and called on the youths to help create a better world.

“We are with the young people of Gaza, we are with the young people of Ukraine,” the pontiff said.

“My young brothers and sisters, you are the sign that a different world is possible,” he said. “A world of fraternity and friendship, where conflicts are not resolved with weapons but with dialogue.”

Many of the youths attending the event spent the night outside in the field, to be ready for the pope’s arrival at 7:45 a.m. (0545 GMT) in advance of heat expected to reach 30 degrees Celsius (86 degrees Fahrenheit) later on Sunday.

“It’s amazing to see just how big the world church is, and how many people are here … and (are) on fire to see the pope,” said Rita Piendl, 19, who came from Germany.

“We want to truly spread hope and love to the world and we really want to make a difference for the better.”

The Catholic Church, which numbers more than 1.4 billion members globally, has grown slightly in recent years but has experienced sliding adherence in Europe.

Sunday’s Mass was part of a week-long series of events in Rome for Catholic youth, tied to the ongoing Catholic Holy Year.

Leo, the first U.S.-born pope, was elected on May 8 by the world’s cardinals to replace the late Pope Francis.