Pope Leo XIV is celebrating Palm Sunday before tens of thousands of people in St. Peter’s Square. The celebration kicks off Holy Week. It began with a procession of cardinals, bishops, priests and laypeople walking into the square carrying olive branches and palm fronds, some intricately braided. Palm Sunday marks Jesus’ triumphant entrance into Jerusalem in the time leading up to his crucifixion, which Christians observe on Good Friday, and resurrection on Easter Sunday. For many people, Leo's first Holy Week recalls the final, suffering days of Pope Francis’ life. He died April 21 last year, on what was Easter Monday.