During the Prayer Vigil in Madrid during World Youth Day, the Blessed Sacrament was exposed for adoration. During this time of prayer before our Lord, our Holy Father Pope Benedict consecrated the Youth of the World to the Sacred Heart of Jesus. 
In 1675 our Lord appeared to St. Margaret Mary Alacoque revealing His Heart, pierced and crowned with thorns. He said to her: “Behold this Heart which has loved so much and yet is so little loved in return.” He asked her to make reparation for the indifference and ingratitude of men and women towards the love of Jesus.
I have heard many beautiful reports of young persons praying and silence during the liturgies of World Youth Day. I myself was impressed by the silence during the Eucharistic prayer at the Opening Mass with Cardinal Rouco Varela. However, my overall experience was very different. When our group stood for the opening ceremonies of the Mass we had to endure hundreds of people behind us shouting “SIT DOWN! SIT DOWN! SIT DOWN!” as we were blocking their view of the video screen. During the Stations of the Cross, a young woman in front of me devoutly genuflected for each station but then continued to chat with the young men beside her. Throughout the Papal Mass people walked about and chatted amongst themselves.
There are a number of excuses for the behaviour – we were very far from the altar, the events were in a foreign language and it was very difficult to follow what was going on. Yet the experience brought to life those words of our Lord to St. Margaret Mary – “This is the Heart which has loved so much and yet is so little loved in return.”
At Cuatro Vientes on Sunday morning, no matter what direction you turned you could not see the end of the crowds. Our Lord suffered greatly for each and every one in this great multitude of soul. He came to be with them on the altar. His vicar on earth, our Holy Father, had come to speak to them. Yet, it seemed as if so few responded to his generosity.
Let us be those souls who console the Heart of Jesus. Let us offer reparation for the indifference of men and women. Let us offer our lives for the conversion of souls. May the Heart of Jesus truly be the King and center of all hearts.
 An unofficial translation of the prayer is available here.