The Spanish youths had come to the Vatican for the celebration of Palm Sunday April 1 and to thank the Pope for visiting Madrid for World Youth Day last August. The Spanish delegation included the World Youth Day orchestra, which played during the papal audience.

While the Pope was with the young people, Vatican officials and representatives of the Brazilian bishops' conference were holding a news conference to talk about plans for the next international celebration of World Youth Day, which will be held July 23-28, 2013, in Rio de Janeiro.

Pope Benedict told the Spanish youths that the World Youth Day experience "can only be understood in the light of the presence the Holy Spirit in the church," who continues to enliven the church and to push believers "to bear witness to the wonders of God."

He told the young people, "You are called to cooperate in this exciting task, and it's worth it to commit yourself to it without reservation. Christ needs you to expand and build his kingdom of charity."

Each and every person has a vocation, a call from God that is the key to each person's holiness and happiness, as well as being a call to create a better world, the Pope said.

The missionary outreach of young people is set to be a key focus of WYD 2013 in Rio, said Vatican and Brazilian officials.

Auxiliary Bishop Eduardo Pinheiro da Silva of Campo Grande, president of the Brazilian bishops' commission for youth, said the "days in the dioceses" that usually precede the main World Youth Day gatherings would be transformed into a "Missionary Week" when young Catholics from around the world travel to Brazil.

The youths' time in dioceses outside Rio will still include a chance to get to know local people and customs, but Bishop da Silva said organizers felt -- and the Vatican agreed -- that more time should be devoted to catechesis, spiritual experiences and encounters that would help young Catholics from around the world learn to share their faith with others.

The news conference was held after a March 29-31 meeting of representatives of bishops' conferences and movements from 99 countries. The meeting included a review of the Madrid experience and a discussion of plans for Rio.

Cardinal Stanislaw Rylko, president of the Pontifical Council for the Laity, which coordinates the youth gatherings, said one of the chief criticisms of the Madrid gathering was that the vast majority of young people -- about 1 million of them -- were unable to receive Communion at the final Mass. Organizers said they had to close the tents where the unconsecrated hosts were stored after a storm.

The Canadian representative, Basilian Father Thomas Rosica, who was director of World Youth Day 2002 in Toronto, said organizers must never forget that logistical problems at such an event have "pastoral and liturgical ramifications and consequences that last long after the event is over."

He said questions still remain about why it wasn't possible to get the hosts out of the tent, and even why so many young people with passes for the Mass weren't allowed in.

"Whatever the real, legitimate circumstances were that caused these situations, let us do everything we can to avoid them in the future," he told the meeting.

Cardinal Rylko told reporters the Madrid experience will help the Brazilians be even more prepared for the unforeseen and unpredictable, but he also said, "World Youth Day is a pilgrimage and pilgrimages always bring challenges."

The cardinal also was asked about plans for the Rio 2013 Way of the Cross celebration, one of the key moments of World Youth Day.

With the event still 15 months away, details are still being worked out, he said; however, the prayer service traditionally has been connected to the local reality -- to the history, culture or suffering of the local people -- so one idea is to have at least one station inside one of Rio's "favelas" or poor neighborhoods.

Archbishop Orani Tempesta of Rio de Janeiro told reporters, "We're still looking at how to do that."