A pilgrim looks on during the Papal Welcome Ceremony at Barangaroo, on Sydney Harbour on July 17, 2008 in Sydney, Australia. Organised every two to three years by the Catholic Church, World Youth Day (WYD) is an invitation from the Pope to the youth of the world to celebrate their faith. The celebration, being held in Sydney from July 15 to July 20, 2008, will mark the first visit of His Holiness Pope Benedict XVI to Australia. By Kristian Dowling/Getty Images.