(BBC) - Pope Benedict XVI has visited Ground Zero in New York, the scene of the 11 September 2001 attacks on Twin Towers, at the end of a six-day tour of the US.
He greeted survivors, fire and police workers, and relatives of some of the 2,749 people who died there.
He also offered prayers for rescuers, victims, as well as "those whose hearts and minds are consumed with hatred".
The Pope will later celebrate Mass at New York's Yankees stadium before flying home.
It will be the conclusion to what observers say has been a successful trip.
His visit has dominated the American media, and demand for the 55,000 tickets for Sunday's Mass has far outstripped supply, reports the BBC's David Willey in New York.
Construction work at the crater-like site of Ground Zero stopped for the ceremony.
After arriving in the popemobile, Benedict knelt in silent prayer, and rose to light a memorial candle, and blessed with holy water what he called "the scene of incredible violence and pain".
He requested "eternal light and peace" for those who died, not only in New York but at the Pentagon in Washington DC and in a Pennsylvania field on 9/11.
"God of peace, bring your peace to our violent world," he said. "Turn to your way of love those whose hearts and minds are consumed with hatred."
The Pope then met 24 people with ties to the tragedy, exchanging a few words with each.
Later, he will hold the second huge open-air Mass of his visit at the stadium, following one at the Nationals stadium in Washington DC on Thursday.
n a personal address on Saturday, Benedict told youths at a New York rally about growing up under the "monster" of Nazism.
With a candour that correspondents say has been a hallmark of this visit, he spoke publicly for the first time about being forced to join the Hitler Youth and being conscripted into the Nazi army.
The Pope has also repeatedly condemned paedophile Catholic priests. More than 4,000 US Catholic clergy have been accused of sexually abusing minors since 1950.
The Church has paid out more than $2bn (£1bn) in compensation and legal fees, most of it since the scandal erupted in 2002.