NEW YORK -- Pope Benedict XVI began the final day of his American journey by blessing the site of the Sept. 11, 2001, terrorist attacks on the World Trade Center and pleading with God to bring "peace to our violent world."

The visit by Benedict to ground zero was a poignant moment in a trip marked by unexpectedly festive crowds anxious to see the former academic who for three years has led the world's Roman Catholics.

Benedict was driven in the popemobile part-way down a ramp now used mostly by construction trucks to a spot by the north tower's footprint. He walked the final steps, knelt in silent prayer for a few moments, then rose to light a memorial candle.

Addressing a group that included survivors, clergy and public officials, he acknowledged the many faiths of the victims at the "scene of incredible violence and pain."

The pope also prayed for "those who suffered death, injury and loss" in the attacks at the Pentagon and in the crash of United Airlines Flight 93 in Shanksville, Pa. More than 2,900 people were killed in the four crashes of the airliners hijacked by al-Qaida.

"God of peace, bring your peace to our violent world," the pope prayed on a chilly, overcast morning. "Turn to your way of love those whose hearts and minds are consumed with hatred."