The day before, a larger-than-expected crowd (1.5 million people) had filled to the seams a perimeter equivalent to 48 soccer stadiums plus an overflow area in a field nearby under an unforgiving sun. It was so crowded the police had to close access to the premises. “If you throw a pin in there it won’t fall on the floor” a policeman told me. As the crowds paraded out through the streets, people in nearby apartment buildings ran water hoses from windows and fences to give the pilgrims a respite and allow them to refill their containers.

Two of them were a little girl and her grandpa. I approached the little girl and asked her to pour water over my head. It felt like a blessing! I thanked them with a traditional Spanish saying: “Dios se lo pague” (May God repay you!). To which the man responded, “No need to repay anything. Your presence here is payment enough. Thank you for coming!”

His response reminded me of a story I heard days earlier. A Spanish man at one of the catechetical sessions told the youngsters in attendance, “I am here to tell you to never be ashamed of your faith. I was scared and I hid it for many years. They made it something political… Your presence here has encouraged me not to be afraid.”

When the Pope arrived in Madrid, I was stationed less than 100 yards from the Apostolic Nunciature, next to a small group of teenage girls from Boston, Milwaukee and Ohio. They had learned a short chant in Spanish and kept repeating it while waving their U.S. flags. “¡Esta es la juventud del papa! ¡Esta es la juventud del papa!” (We are the pope’s youth; we are the pope’s youth!). An elderly Spanish woman, in good spirits and with a great sense of humor, approached them and pointing to herself started singing along, “¡Esta es la juventud del papa!¡Esta es la juventud del papa!” I couldn’t help it but to smile.

Another time, as we walked through Madrid’s streets, a colleague pointed one of a few balconies that had the pope’s symbols on display and said, “In the old times almost every balcony and window would have displayed the Vatican’s flag or a picture of the pope.” To which I responded, “This is a very different country now, but it is my hope that by witnessing all of these Catholic young people from around the world, so filled with energy and so proud of their faith, many will realize, ‘wait a minute, we used to be like that’ and that that will encourage them to search deeper and rediscover their Christian heritage.”

The pope gave the young people many important messages. All of them can be retrieved from the Vatican’s Website (www.vatican.va). He told them to let no one take peace from them; to never be ashamed of Christ; to remain firm in the faith; and that one cannot be a Catholic away from the community of believers. He encouraged them to get to know Christ personally, to pray with the Word of God often and to build their lives on solid ground; to seek the truth “without adjectives” and not look the other way when confronted with human suffering.

“Your friends will want to know how you have changed after being in this lovely city with the Pope and with hundreds of thousands of other young people from around the world. What are you going to tell them?” the pope asked after the Mass. “I invite you to give a bold witness of Christian living to them. In this way you will give birth to new Christians and will help the Church grow strongly in the hearts of many others.” And also, “I entrust all of you present with this task: make the knowledge and love of Jesus Christ known to the whole world! He wants you to be the apostles of the twenty-first century and the messengers of his joy. Do not let him down!”

Looking back, I hope that, like Mary, we will be able to ponder in our hearts all that we saw and heard. How our attendance at World Youth Day will impact each one of us and the people to whom we give testimony, depends on the generous response of each heart.

I sure hope, though, that the good Lord gives me a chance to see the impact that WYD 2011 will have on the long run in the host country and the rest of the Old Continent. From what we can tell, the New Evangelization of Europe has begun with a game-changing home-run in the pope’s own backyard. Well done Spain! Thank you, young Catholics of the world!

Mar Muñoz-Visoso is assistant director of media relations at the United States Conference of Catholic Bishops