Pope Benedict XVI has left Rome for the US, where he will meet US President W George Bush and deliver an address to the UN in New York.
The Pope is also expected to address a sex abuse scandal that has rocked the Catholic Church in the US.
He will touch down at Andrews Air Force base outside Washington DC at around 9pm Irish time this evening where he will be greeted by Mr Bush and First Lady Laura Bush.
His first engagement will be a visit to the White House on Wednesday morning.
As well as meeting with US bishops and leaders of other faiths, the Pope will celebrate mass before an expected audience of 46,000 at Washington's baseball stadium, Nationals Park, on Thursday.
He travels to New York on Friday where security is expected to be tight for his address to the UN and a visit to Ground Zero. He will also celebrate mass at St Patrick's Cathedral and the city's Yankee stadium.
It is widely expected that at some stage during his visit, the Pope will address the scandal of sex abuse in the US Catholic Church, which has run up close to $2bn in legal fees and settlements and forced five dioceses across the country into bankruptcy.
