History is taking place in Great Britain.
Pope Benedict XVI is the first pope to make a state visit to the United Kingdom since Pope John Paul II's 1982 visit.
The Papal visit to Britain begins in Edinburgh, where Britain's 84-year-old Queen Elizabeth II will greet the 83-year-old Pope before rallying Britain's 6 million Catholics at open air masses and parades through the streets in his armored car nicknamed the Popemobile.
But this four-day, $20 million visit is already mired in controversy. The cloud of the sexual abuse scandal in the Catholic Church is hanging over events.
Belgian investigators just published a report detailing sexual abuse by priests in nearly every diocese in that country.
Some of the victims were reportedly as young as two years old.
British victims of abuse are demanding more than just an apology from the Pope. They want money for counseling and they want the Vatican to throw open its files on abuse.
Protests are also planned by those who oppose the Pope's views on condom use, homosexuality and the ordination of women.
When asked about the sex scandals, he said "the revelations were a shock to him" and "caused great sadness."
He acknowledged that "the authority of the church was not sufficiently vigilant nor quick or decisive enough to take the necessary measures."
There must be "just punishment" for the perpetrators and they must be kept away from youths, he added.
This morning, Brits are bristling at comments made by a Papal aide who likened Britain to a third world country because of the large immigrant population.
Cardinal Walter Kasper told a German magazine, "Sometimes, when you land at Heathrow, you think you have entered a third world country."
Kasper was due to accompany the Pope on this trip but has stayed in Rome, apparently because of ill health.
Papal Events Include Masses, Musical Performances
Despite the controversy, the Pope's state visit includes an open air mass in Glasgow with a performance by singer Susan Boyle.
"It's something I've really wanted to do," Boyle said after a rehearsal. "I'm a very devout Catholic and it's something I've dreamed of."
However, ticket sales for Papal events in Britain have been sluggish.
Organizers hoped for a crowd of 100,000 at an open air mass in Glasgow Thursday afternoon.
They've since revised their estimate down to 65,000.
On Thursday night, the Pope heads to London for meetings with religious and political leaders, private and public celebrations of mass and a prayer vigil in Hyde Park.
His final stop on this tour will be Birmingham in the English Midlands where he will beatify a Nineteenth Century cardinal, Henry Newman.
In attendance for the ceremony will be Jack Sullivan, a 71-year-old American Catholic deacon and the benefactor of the miracle needed for Newman's beatification.
Apparently, Sullivan was freed from crippling back pain, which had left him bed-ridden and barely able to breathe.
ABC News' Phoebe Natanson and Associated Press contributed to this report.