Pope Benedict will face the toughest crowd of his four-month-old papacy when he visits the World Youth Day festival in Cologne, Germany, where more than 400,000 lively young Catholics are expected to greet him.
Although the youngsters from almost 200 countries are guaranteed to give the 78-year-old German a hearty reception, Benedict will come under scrutiny not only for what he tells his audience but the amount of charm and warmth he can muster.
Benedict is clearly not as comfortable with the limelight as his predecessor Pope John Paul - a former actor who relished a chance to bring a crowd of millions to its feet and often did so at the youth jamborees he launched in the 1980s.
While Benedict has overcome some stage-fright since his April election, leading cardinals have said he will not attempt to replicate John Paul's winning formula but find his own style.During his regular papal audience on Wednesday, Benedict asked for prayers for his "apostolic pilgrimage".
"This is an important Church event and we all hope it will bring much spiritual fruit for the entire Church, which is counting much on the commitment and witness of young people to the Gospel," he said, reports Reuters.
According to The Belfast Telegraph speaking before the Mass, the head of the German Bishops' Commission for Youth, Dr Franz-Josef Bode, said that 350,000 young people, including 120,000 from overseas, have already taken part in the "Days of Encounter" in parishes all over Germany in the run-up to yesterday.
Up to 800,000 people are expected to attend the final Mass outside Cologne on Sunday morning. Grey skies and drizzle greeted young Catholics arriving in Cologne yesterday. But they cheered nonetheless, waving national flags and shouting boisterous "olas" and "hellos".
"It's the most peaceful invasion of all time," popular newspaper Bild newspaper wrote. Bemused residents of Germany's fourth-largest city smiled patiently as pilgrims thronged outside its massive Gothic cathedral, some strumming guitars, others studying maps to find one of three Masses opening the "Catholic Woodstock".
"The whole city is full of young people," Cologne's Cardinal Joachim Meisner told an opening news conference, adding how proud he was to have been one of those involved in the planning of the €100m festival over the last three years.