In the foreground, more than 3,000 young people settled on the ground, as Archbishop Christopher Prowse of Canberra, Australia, started his address.

"At a time of so much deadness and negativity, we are the people of hope," the archbishop's voice boomed over loudspeakers. "We are the missionary people, the people of mercy sent out by God, who hold Jesus close to us."

The International Evangelization Center, close to Krakow's Blonia Park, was a key feature of World Youth Day, tasked with inspiring and encouraging vocations to the priesthood and religious life.

Robert Kosciuszko, its Polish spokesman who coordinates volunteers from all continents, said each language group was asked to prepare a program of prayers and testimonies during the weeklong festival.

Those sensing a call to the priesthood, Kosciuszko explained, were referred to a special Vocations Center in Krakow's main sports stadium, which ran daily prayer meetings and discussions on subjects from sexuality to interfaith dialogue.

Bishop Joseph A. Pepe of Las Vegas agreed that World Youth Day offers an important opportunity for fostering vocations, with over a third of current U.S. seminarians citing previous Youth Days as a major influence.

At least one of his deacons, Bishop Pepe said, felt his calling at World Youth Day in Madrid in 2011 and plans to work in Russia after ordination.

"This is very much an evangelical moment when it comes to considering the priesthood and religious life," the bishop told Catholic News Service in Krakow July 29. "The young men and women who come here see youthful priests and sisters around them – they seem dynamic and happy, and this encourages them to make inquiries."

With admissions to the Catholic priesthood and religious orders now dwindling in much of the world, center volunteers say youth events like this provide a major forum for encouraging initial signs of interest in the religious life.

Wojciech Kuczynski, a Polish novice with the Society of the Divine Word, said he discovered his vocation while attending a youth vigil after the April 2005 death of St John Paul II, after "a life of drugs and rock music" that included "dabbling in satanism." Kuczynski hopes to be ordained a priest in 2018.

"The Holy Spirit, wherever it goes, opens doors to growth and maturity," said Father Bartlomiej Dudek, a Polish priest from Przemysl ministering at the center. "Vocations can only be inspired by the Holy Spirit, not in any other way. And the World Youth Day is truly spirit-filled – God speaks here to people's hearts."

From Tanzania, Bishop Gervas Mwasikwabhila Nyaisonga of Mpanda said his vocation was confirmed while attending a Catholic youth event.

Young people everywhere need "contacts and connections," the bishop said, and mass festivals like this "remind them they're valued and taken seriously by the church."

"While youngsters feel their religiousness is accepted here, they don't always feel it's accepted at home – so we encourage them to maintain their own culture and identity, provided it's Christian," Bishop Nyaisonga told CNS.

"But many feel, after an experience like this, they also owe something to the church. If they're influenced and inspired in the right way, they may well choose to embrace the religious life," said the bishop, who came to Krakow with 430 lay Catholics and 16 priests from Tanzania.

Holy Spirit Sister Catherine Wu Jialin from China's Hebei province, said the several dozen Chinese Catholics who made it to World Youth Day all had to "come in various guises," since the Beijing government would not have permitted it officially. But she said at least one Chinese visitor is now considering the priesthood after having the opportunity "to mix with like-minded young Catholics from around the world."

"There are huge difficulties in the path of young people who feel the call this way," Sister Catherine told CNS. "But we can't underestimate the importance of an event like World Youth Day in giving them the courage and confidence to face up to such challenges."

Back at the vast red-and-yellow circus tent, the morning liturgy concluded and the International Evangelization Center rock band played a specially composed youth anthem, "Light of My Life."

Across the field, priests waited to hear confessions, while hundreds of jubilant youngsters from dozens of countries streamed out of the arena, dancing and waving their hands.

Fenola Lyons said several Australian friends were thinking about becoming nuns, "despite pressure to form relationships and opt for family life."

Father Paul Winter, vocations director for Australia's Lismore Diocese, said vocations are a "delicate plant" and won't always be recognizable while World Youth Day is still underway.

But the 2008 World Youth Day in Sydney provided a magnet for Australian vocations, Father Winter recalled, not just for the priesthood and religious life, but for other forms of Catholic commitment as well. If the enthusiasm and fervor can be maintained and channeled, the church will derive great benefits.

Archbishop Prowse agreed.

"The youth continue to surprise us with their joy and hope – in many quarters, it's said young people aren't interested in the faith and Christianity, but this World Youth Day has once again proved this totally wrong," the Australian archbishop told CNS.

"Young people are giving the world an example, and we should be thankful to them for it – and to this festival for fostering vocations to the religious life," he said.