Sydney  - A helicopter-borne Pope Benedict XVI swooped over a Sydney racecourse where 235,000 pilgrims spent a chilly overnight vigil in readiness for the Sunday Mass that closes a week-long Catholic youth festival.

Organizers of World Youth Day say as many as 500,000 worshippers could flock to the venue, going into the record books as Australia's biggest-ever crowd.

It's certainly one of the most joyous. Youngsters from over 170 countries waved their national flags and cheered the 81-year-old pontiff.

The religious jamboree is in its second day at Randwick Racecourse. On Saturday, Benedict spoke to those who had marched a 9- kilometre route that took them over the famous Harbour Bridge, which was closed to traffic for the occasion.

"God has made us for one another, and only through God and his church can we find the unity we seek," the 81-year-old pontiff told the youngsters before they bedded down for the night. "In the end, life is not about accumulation. It's much more than success."

A condign apology to those who have been sexually abused by the clergy assured Pope Benedict a grand reception when he climbed into the popemobile for a drive through the 22-hectare location. (dpa)