The July 12-21 trip included several days of rest as well as meetings with representatives of Australia's government, Catholic Church and native fauna.
Relaxing July 13-16 at an Opus Dei-run centre outside Sydney, the Pope was treated to a visit from representatives of Sydney's Taronga Park Zoo, including a koala bear, a wallaby joey and an echidna.
Once the public part of his trip began, Pope Benedict spent his days combining World Youth Day activities with elements of a pastoral visit to Australia.
During a July 19 Mass at Sydney's St. Mary's Cathedral, the Pope apologized to Australian victims of clerical sexual abuse.
The Pope said, "I am deeply sorry for the pain and suffering the victims have endured and I assure them that as their pastor, I, too, share in their suffering."
In his homily for the Mass, which included the consecration of the cathedral's new altar, Pope Benedict prayed for the rededication and renewal of the Catholic Church throughout Australia and asked the country's priests and religious to support fully the bishops' programs for protecting young people, assisting victims and bringing perpetrators to justice.
Meeting Australian Prime Minister Kevin Rudd and other government officials July 17, Pope Benedict praised efforts to promote reconciliation with the country's indigenous peoples, who had long been oppressed. Dance, chants and art from the aboriginal and Torres Strait Islanders were included at many of the papal events, and elders from the two groups prominently welcomed the Pope to their land.
The Pope's primary focus was on the thousands of young Catholics who came from some 170 countries to participate in the July 15-20 World Youth Day and reflect on its theme, "You Will Receive Power When the Holy Spirit Has Come Upon You, and You Will Be My Witnesses."
More than 200,000 young people attended the July 19 vigil at Randwick Racecourse and, police said, some 350,000 people were at the track for the July 20 closing Mass. World Youth Day officials estimated the crowd at 400,000.
"Do not be afraid to say 'yes' to Jesus, to find your joy in doing His will, giving yourself completely to the pursuit of holiness," the Pope said in his homily for the Mass, which included administering the sacrament of Confirmation to 24 young people from nine countries.
The world needs the transforming power of the Holy Spirit, he said at the Mass.
"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," he said.
The Pope told the young people that opening their hearts to Jesus and co-operating with the gifts of the Holy Spirit would transform their lives and help them bring a life-giving witness to the rest of the world.
Repeatedly during the trip, Pope Benedict described the Holy Spirit as God's creative, life-giving and courage-giving force.
The Pope also spoke often of the need to protect the environment and respect the gifts of God's creation, but he made it clear to the young people that human beings are God's greatest creation.
"At the heart of the marvel of creation are you and I, the human family, 'crowned with glory and honour' ” as the Psalms say, he told the young people at the July 17 World Youth Day welcoming ceremony.
Just as the natural environment can be destroyed by selfishness and exploitation, he said, so too can human life be destroyed or damaged by not recognizing human dignity and the plan God has for each person's life.
"Experience shows that turning our back on the creator's plan provokes a disorder which has inevitable repercussions on the rest of the created order," he said.
God gave people the freedom to make choices so that they would choose truth, goodness and beauty, the Pope said.
"Our hearts and minds are yearning for a vision of life where love endures, where gifts are shared, where unity is built, where freedom finds meaning in truth and where unity is found in respectful communion," he said.
The young pilgrims were not the only young people on the Pope's mind and on his itinerary. After watching a dramatic World Youth Day presentation of the Stations of the Cross through the streets of Sydney, the Pope went to visit young people recovering from alcohol and drug abuse and other disadvantaged people being helped by the Alive program of Catholic Social Services. The Pope told them they were "ambassadors of hope" to their peers because they have had the courage to turn their lives around.
"The choice to abuse drugs or alcohol, to engage in criminal activity or self-harm, may have seemed at the time to offer a way out of a difficult or confusing situation," he said. "You now know that instead of bringing life, it brings death."
The Pope told them that Jesus loves them unconditionally and prayed that the Holy Spirit would be with them and would make them witnesses of the joy that comes from choosing to cherish the life God has given them.
Pope Benedict also set aside a morning to encourage ecumenical and interreligious dialogue in Australia by holding separate meetings with Christian leaders and with representatives of Australia's Jewish, Muslim, Buddhist, Hindu and Zoroastrian communities.