NEW YORK - Tens of thousands of American Catholics cheered for Pope Benedict XVI at a Yankee Stadium Mass on Sunday, as the pontiff ended his U.S. trip praising this nation's freedom and urging the American church to overcome adversity.

The pope also visited the site of the Sept. 11, 2001, terrorist attacks. Under gray skies, he walked to a memorial spot to light a candle and pray. "God of peace, bring your peace to our violent world," he said. "We ask you in your goodness to give eternal light and peace to all who died here."

He also prayed for ill and injured survivors of the attacks and still-grieving families.

The solemn morning ceremony was a stark contrast to the afternoon Mass, which transformed Yankee Stadium into an open-air cathedral, with a white altar over second base.

"The Catholic community in this nation has been outstanding in its prophetic witness in the defense of life, in the education of the young, in care for the poor, the sick and the stranger in your midst," the pope told the crowd of more than 57,000 people. "On these solid foundations, the future of the church in America must even now begin to rise."

People from around the country came to the Mass, braving immense crowds and exceptional security run by the U.S. Secret Service and New York police that included metal detectors and bag searches.

"It was spectacular," said Mary Voss, who came to the Mass from Smyrna, Ga., with her husband, Paul, and three of their children.

"I love this pope because I think he hits head-on all these controversial topics," Voss said. She said coming to the Mass was the best gift they could give their children, "to feel so in love with the leader of our church."

Benedict spoke about the American church, saying "in this land of freedom and opportunity, the church has united a widely diverse flock in the profession of the faith."

"The face of the Catholic community in your country has changed greatly," he said. "We think of the successive waves of immigrants whose traditions have so enriched the church in America."

The pope, who has spoken of the fast-growing U.S. population of Hispanic Catholics, ended his remarks in Spanish. The language switch was met with cheers.