Pope Francis prayed at the 9/11 Memorial before a crowd of onlookers, shook hands with leaders of the city's Jewish, Sikh and Muslim communities, and then talked about suffering, healing and unity.
"I feel many different emotions standing here at Ground Zero, where thousands of lives were taken in a senseless act of destruction," Francis said. "Here, grief is palpable."
The pope said he met with family members of first responders who died in the aftermath of the attacks on Sept. 11, 2001, in which more than 2,600 people were killed.
But the memorial also reminded him of mankind's best qualities, he said.
"Here, amid pain and grief, we also have a palpable sense of the heroic goodness which people are capable of, those hidden reserves of strength from which we can draw," Francis said. "In the depths of pain and suffering, you also witnessed the heights of generosity and service."
He closed with a message of unity, telling the crowd that religious differences should never get in the way of peace.
"It is a source of great hope that in this place of sorrow and remembrance I can join with leaders representing the many religious traditions which enrich the life of this great city," Francis said. "I trust that our presence together will be a powerful sign of our shared desire to be a force for reconciliation, peace and justice in this community and throughout the world."
Peace comes only through unity, Francis said. And peace is the only way in which the legacy of those who lost their lives on Sept. 11, 2001 will not be forgotten.
"Instead, they will be present whenever we strive to be prophets not of tearing down but of building up, prophets of reconciliation, prophets of peace," Francis said.