From The Vatican:
More than 250 thousand people gathered this morning to attend Palm Sunday Mass, which Pope Francis celebrated in St. Peter's Square. For the thirteenth consecutive year, the olive trees and branches that adorned St. Peter's Square and were distributed to the faithful present were a gift from the Puglia region of Italy. The floral design that decorated the altar this year reflected the geography of the five continents: 60,000 olive branches were mixed with grasses and peach leaves, thyme, myrtle, ferns, strawberries, broom, lilies, wallflowers, and celery-leaved buttercups. The two centuries-old olive trees that were placed at the foot of the statues of St. Peter and St. Paul in the square will be planted in the Vatican Gardens after the Mass.
The celebration began at 9:15am with a procession of palm branches in which 620 persons—cardinals, bishops, priests, deacons, children, and lay persons—participated. Some 2,000 palm branches were brought in from the Ligurian towns of San Remo and Bordighera in Northern Italy, as has been the tradition now for five centuries. The Pope entered the square while the choir and crowd sang the Hosanna. After reaching the foot of the square's obelisk, the Pope blessed the palms and olive branches of those in the square.
The procession then continued to the altar on the Sagrato of the Basilica. The Pope carried one of the three-metre long palm branches, which had been artistically braided so as to represent the Holy Trinity. Concelebrating with the Pope were: Cardinal Agostino Vallini, vicar general of the Diocese of Rome; Cardinal Stanislaw Rylko, president of the Pontifical Council for the Laity; and, Archbishop Filippo Iannone, O. Carm., vice gerent of the diocese of Rome.
The choir sang the Kyrie while the Pope venerated and incensed the altar. The Liturgy of the Word included readings from Isaiah and St. Paul's Letter to the Philippians. After the Gospel reading of the Passion, proclaimed by three deacons, the Pope's homily focused on three central aspects: Joy, the Cross, and Youth. His full homily can be read below.
As part of the closing rites of the Mass, the Pope prayed the Angelus. Then, re-entering the Vatican walls, the Pope took a long route through the square, greeting those gathered and being especially attentive to the young and the sick.