Pope Francis crowned a packed tour of New York on Friday by celebrating mass at Madison Square Garden, after greeting crowds in Central Park and praying for world peace at the 9/11 Memorial.
Around 20,000 people packed into MSG, the home of the Knicks basketball team, to take communion in the presence of the 78-year-old pontiff.
The city's premier concert venue, originally booked Friday by Billy Joel, was lit up by the singer's own crew who turned it into a serene and beautiful venue for Catholics to celebrate mass.
Once again, the hugely popular pope focused on society's most vulnerable during his last public remarks in America's financial capital, a city of extreme wealth and poverty.
He praised big cities for their diversity but called on worshippers not to forget "the faces of all those people who don't appear to belong, or are second-class citizens."
"They are the foreigners, the children who go without schooling, those deprived of medical insurance, the homeless, the forgotten elderly," he said.
It marked his last public engagement in New York before he leaves for Philadelphia, where he will greet huge crowds at the Festival of Families, which takes place every three years.
Earlier on Friday, he led a gathering of 700 at Ground Zero, where he paid tribute to the nearly 3,000 victims and those who were first in line responding to the 11 September attacks.
The head of the world's 1.2 billion Catholics led a multi-faith prayer for world peace bringing together Hindu, Buddhist, Sikh, Greek Orthodox, Muslim and Jewish leaders.
"In this place of pain and remembrance I am full of hope," said the Argentine pope.
"I hope our presence here sends a powerful sign of our wish to share and reaffirm the wish to be forces of reconciliation, forces of peace, of justice."
After an impassioned early morning speech at the United Nations, and the grave solemnity of Ground Zero, Francis was welcomed in song and laughter on a heartwarming visit to a Catholic school in New York's East Harlem neighborhood Friday afternoon.
Beaming and relaxed, even submitting to a selfie or two, the pope -- who is already a week into an exhaustingly packed American tour -- seemed to come alive during the hour he spent with the children at Our Lady Queen of Angels school.
Flag-waving youths chanted "Holy Father, we love you!" as the pope smiled and grasped hands, before heading inside the school to a welcome from a choir of largely black and Latino students.
Tenderly patting heads, Francis toured the classroom chatting in Spanish, before meeting migrant workers and their families who presented him with gifts, including a set of tools on behalf of the Big Apple's army of day labourers.
As in his historic speech to the US Congress the day before, Francis cited the legacy of Martin Luther King.
"One day he said, 'I have a dream'," said Francis. "His dream was that many children like you could have access to education."
"Don't forget about that. Today we want to keep dreaming," said the pope, whose reform-minded approach and humility has earned him a rapturous welcome in America.
From Harlem, Francis set off for Central Park, where he was greeted by hysterical screams of joy from a sea of 80,000 people who waited to catch a glimpse of him.
Many were Latino immigrants who said they felt a special connection to the pope, coming together in a carnival-like atmosphere dotted with yellow and white Vatican flags and the colors of South American countries.
He began the day at the UN General Assembly by offering his vision of a better world in a wide-ranging speech.
Francis touched on the persecution of Christians, the Iran nuclear deal, drug trafficking -- "silently killing millions" -- and the rights of girls to an education.
The first Latin American pope -- who has seen his own country suffer economic crises -- called on the UN Security Council and financial lenders to "limit every kind of abuse and usury."
He also gave his latest passionate plea to protect the environment, as he voiced confidence that a looming UN summit on climate change would reach "effective" agreement in Paris.
The pope offered a strong endorsement of Iran's agreement with the United States and five other world powers to limit its nuclear program -- a deal vehemently opposed by many US lawmakers.
Francis has an avid following even among non-Catholics for his embrace of causes such as climate change and his progressive approach to social issues.
But at the UN, he signaled that the church was not ready to champion transgender rights, an issue of growing importance in the United States as gay equality becomes mainstream.
"We recognize a moral law written into human nature itself, one which includes the natural difference between man and woman and absolute respect for life in all its stages and dimensions."
Francis has enjoyed a remarkably warm response in the United States, with President Barack Obama welcoming him personally on Wednesday and championing the pontiff's leadership.
