Under tight security in St. Peter’s Square in Rome, tens of thousands of worshipers from around the word thronged to a Mass celebrated by Pope Francis on Easter Sunday.

The pope began the day with a post on Twitter: “Our faith is born on Easter morning: Jesus is alive! The experience is at the heart of the Christian message.” He then delivered the papal blessing “Urbi et Orbi” (“To the City and to the World”) from the central balcony of St. Peter’s Basilica.

The night before, Francis celebrated an Easter Vigil service at St. Peter’s, where he baptized eight adults into the Roman Catholic faith, including a Nigerian migrant, John Ogah, called a hero in Italy for foiling a robbery.

In his message on Sunday, the pope called for peace in a world marked by war and conflict. He cited a need to end the “carnage” in “the beloved and long-suffering land of Syria.”