Pope Benedict XVI was the third head of the Roman Catholic Church to visit the United States.
Crowds were waiting to see him, flags were flying and souvenir shops had turned out an array of mementos.
After the Pope celebrated Mass in Washington, President George Bush is said to have whispered to him: "Awesome speech".
The visit was an opportunity for the Pope to directly address Church leaders about the child sex scandals which have rocked the institution.
But Pope fervour continued unabated throughout the six-day tour - with huge demand for tickets to open-air Masses.
Addressing the United Nations on Thursday, the Pope called for member states to work together to solve the world's crises.
Pope Benedict also became the first Roman Catholic leader to visit a synagogue in the US.
He celebrated three years as head of the Church at a Mass at New York's 150-year-old St Patrick's Cathedral.
A Young Catholics Youth Rally at St Joseph's Seminary in New York was more like a pop concert.
And the equally enthusiastic crowd at New York's Yankee stadium started a Mexican wave as the Pope arrived to celebrate Mass.
The Pope travelled to the site of the 11 September 2001 attacks in New York.
He knelt at an altar at the site, which is to become a memorial, and prayed for the memory of the more than 2,900 people who died in New York, Washington and Pennsylvania that day.
There's no place like Rome: After his visit to Ground Zero and a final Mass, the Pope, and his red shoes, will head back to the Vatican.