Thousands of school children from all over the UK travelled to London for an assembly with a very special guest - the Pope!
It was all part of day two of the head of the Catholic church's four-day tour of the UK.
Pope Benedict XVI flew into London on Thursday night after celebrating a huge open-air Mass in Glasgow.
Hundreds of well-wishers gathered to welcome the Pope to England's capital before he began Friday's busy schedule.
As well as joining up to 4,000 school children for the assembly, he later met the head of the Church of England - the Archbishop of Canterbury.
The Pope landed in Edinburgh on Thursday morning and was greeted by the Queen, before touring the city in his Popemobile.
His visit is very special for the millions of Catholics in Britain as it's the first time a pope has visited since 1982.
The Pope said he wanted to "extend the hand of friendship" to the whole of the UK during his trip.
About 70,000 people cheered and waved flags as the Pope arrived to organ music and hymns at Bellahouston Park in Glasgow.
Britain's Got Talent star Susan Boyle entertained cheering crowds while they waited for the Pope to arrive.
The Pope has a lot of followers, but there are also lots of people who don't agree with what he stands for.
In recent years, it's become clear that some children in the care of Catholic priests have been mistreated.
The Pope did apologise earlier this year in a letter, but he's been accused of not doing enough to uncover exactly what went on.
Pope Benedict will also visit Birmingham before flying home to Vatican City on Sunday.