Pope Benedict XVI celebrated mass on Sunday afternoon at Yankee Stadium in New York City before a crowd of nearly 60,000 people, blessing the faithful and telling Americans to use their freedoms wisely.
The Pope beamed before a joyous crowd of 57,000, hours after making a solemn stop to pray at the site of the Sept. 11, 2001, attacks at the World Trade Center.
He called the mass "a summons to move forward with firm resolve to use wisely the blessings of freedom, in order to build a future of hope for coming generations."
He also repeated a core message of his six-day pilgrimage - that faith must play a role in public life, citing the need to oppose abortion.
The unwavering truth of the Roman Catholic message, he said, guarantees respect for the dignity of all "including the most defenceless of all human beings, the unborn child in the mother's womb." The crowd applauded the line.
The Catholic crowd who filled the baseball stadium to celebrate mass clapped and waved handkerchiefs in the Vatican's colours - white and yellow.
Outside the stadium, two dump trucks filled with sand blockaded 161st Street before the mass to provide an extra level of security.
A white altar was placed over second base and the papal seal covered the pitcher's mound, suspended by white and yellow ribbons.
Earlier on Sunday, the Pope visited Ground Zero, blessing the site and leading prayers for the more than 2,700 people who died there.
He was driven in the Popemobile part of the way down a ramp now used mostly by construction trucks to a spot by the north tower's footprint.
Under grey skies, he got out, walked the final steps and knelt in silent prayer for a few moments.
Surrounded by about two dozen people directly affected by the events of 9/11 - including rescue workers and firefighters - he then rose to light a memorial candle, pray and bless the site with holy water.
The pontiff asked for God to heal those hurt in the attack and "all those who lost loved ones in this tragedy."
He also appeared to pray for the people responsible for the attacks.
"God of peace, bring your peace to our violent world, peace in the hearts of all men and women and peace amongst the nations of the Earth. Turn your way of love to those whose hearts and minds are consumed with hatred," he said.
Joining the Pope at the site were survivors of the Sept. 11, 2001, attacks on the office towers and relatives of those who died, as well New York Mayor Michael Bloomberg and Cardinal Edward Egan.
With files from the Associated Press