Pope Francis celebrates Palm Sunday Mass, in St. Peter's Square at the Vatican, Sunday, March 24, 2013. The new pontiff arrived in an uncovered vehicle to start solemn Holy Week ceremonies, which lead up to Easter, Christianity's most important day. Francis wore bright red robes over a white cassock and presided over the Mass from an altar sheltered by a canopy on the steps of St. Peter's Basilica. (AP Photo/Andrew Medichini), APTOPIX