POPE Francis has joined hundreds of thousands of the faithful for the last and biggest event of his six-day US visit - a mass on Philadelphia's grandest boulevard.
Riding through the streets in his open-sided pope-mobile, the pontiff waved to cheering, sceaming, singing, flag-waving crowds as he made his way up the Benjamin Franklin Parkway and reached the altar at the foot of the broad steps of the Philadelphia Museum of Art.
It was the final stop on his itinerary before the 78-year-old pontiff returns to Rome.
Organisers predicted a crowd of one million, although there were fears that the unprecedented security, including airport-style bag searches, crowd-control channels and blocked-off streets, had scared many people away and would keep numbers down.
En route to the mass, Francis stepped off his pope-mobile to see an art installation with particular meaning for him: Inside the grotto outside Philadelphia's cathedral were 30,000 white knotted ribbons, each representing a personal hardship or societal challenge.
The exhibit was inspired by one of Francis's favourite paintings, Mary, Undoer of Knots, showing Mary untangling a long ribbon symbolising life's difficulties. The painting hangs in a church in Germany, where then-Rev Jorge Mario Bergoglio saw it while studying in the mid-1980s.
Earlier in the day, in a gesture of reconciliation, he met victims of child sexual abuse and told them he was "deeply sorry" for the times they came forward to tell their story and were not believed. He assured them that he believes them and that bishops will be called to account for what they did.
"I pledge to you that we will follow the path of truth wherever it may lead," Francis said in Spanish. "Clergy and bishops will be held accountable when they abuse or fail to protect children."
Then he went into a meeting with US bishops in town for a Catholic festival on the family and told them the same thing face-to-face.
"God weeps" over what was done to children, he said.
Francis's journey also took him to Washington and New York. Along the way, he drew large and adoring crowds, met president Barack Obama, visited Ground Zero and addressed Congress and the United Nations, calling for urgent action on climate change and poverty.
