Pope Benedict XVI (web|news|bio) urged young people Sunday to reject what he said was the "spiritual desert" spreading throughout the world and to embrace Christianity to build a new age free from greed and materialism. At a Mass before more than 200,000 young Roman Catholic pilgrims in Sydney, Benedict said "the world needs renewal" and challenged them to be the agents of change. "In so many of our societies, side by side with material prosperity, a spiritual desert is spreading: an interior emptiness, an unnamed fear, a quiet sense of despair," the pontiff said.

The 81-year-old pope said it was up to a new generation of Christians to build a world in "which God's gift of life is welcomed, respected and cherished - not rejected, feared as a threat and destroyed."

The aim was "a new age in which hope liberates us from the shallowness, apathy and self-absorption which deadens our souls and poisons our relationships," he said.

Sunday's Mass wraps up the church's six-day World Youth Day festival in Sydney that has drawn massive crowds to Australia's largest city, and has been watched on television by a global audience estimated to be in the hundreds of millions.

The Mass, delivered at a horse racetrack filled with pilgrims who had camped out overnight, comes a day after the pope made a forceful apology for the sexual abuse of children by Australia's Roman Catholic clergy. The apology is part of an effort that began in the United States to publicly atone for what he called evil acts by priests.

In his apology Saturday, Benedict said: "I am deeply sorry for the pain and suffering the victims have endured and I assure them as their pastor that I too share in their suffering," Benedict said in Sydney's St. Mary's Cathedral.

He said he wanted "to acknowledge the shame which we have all felt" and called for those responsible to be "brought to justice." The acts were "evil" and a "grave betrayal of trust," he said.

But the pope's apology was not enough to satisfy representatives of the victims of clergy sexual abuse, who said it must be backed by Vatican orders to Australian bishops to stop what they say are efforts to hide the extent of the problem and block survivors' attempts to win compensation.

Sunday's events wrap up a busy four-day schedule for Benedict in which he touched on all the major themes of his three-year-old papacy, including the need to rejuvenate what he says is a church in "crisis" in the West because people are losing their faith in God.

He also stressed the need for mankind to protect the environment and end its "insatiable consumption" of the world's resources. He continued to reach out to other faiths, telling leaders of Islam and other religions they must unite against those who were threatening the world with "sinister and indiscriminate violence."

The pope flew over the scene early Sunday in a helicopter - dubbed "the holy-copter" by bleary-eyed pilgrims below - to see the assemblage amassed on the track with a jumble of sleeping bags, backpacks and other personal items.

He later took a slow drive through the crowd, stopping once to plant a kiss on the forehead of a toddler held up to the popemobile's window. Pilgrims from more than 160 countries gave him a rock-star welcome, waving the flags of their nations, cheering and chanting: "Benedicto!, Benedicto!" - the pope's Italian name.

The pope, who was due to leave Australia for the Vatican on Monday, said the next Roman Catholic youth festival would be held in Spain in 2011.

"I look forward to seeing you again in three years' time," he said.

Written By KRISTEN GELINEAU

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