Young Catholics mass in Rome

The "popemobile" took nearly an hour to get through the crowd

More than a million young Roman Catholics from around the world have massed at a university campus on the outskirts of Rome to celebrate the Vatican's World Youth Day with Pope John Paul.

The gathering is the biggest so far of the Catholic Church's jubilee year.

The Pope spent two hours greeting participants and listening to a programme of music from around the world, which ended with a spectacular fireworks display.

"Tonight they heard us in Rome," he told the crowd from a huge wooden altar platform. "And they will never forget it."

Words of support

Rome's largest crowd in living memory

The 80-year-old pontiff urged the young people who had gathered to resist being "swallowed up by mediocrity".

And he told them he realised it was not easy for the youth of today to be true to their Christian faith.

"I am thinking of how difficult it is in today's world for engaged couples to be faithful to purity before marriage," he said.

The BBC's David Willey in Rome said that despite his ailing health, the Pope appeared revitalised by the huge crowd.

'Catholic Woodstock'

City officials said the jamboree - which some commentators have called a "Catholic Woodstock" - was Rome's biggest crowd in living memory.

Nuns rubbed shoulders with girls in bikinis

It took the Pope all of 45 minutes to drive slowly through the throng on his "popemobile".

It was Rome's hottest weekend of the year, and the crowds were frequently hosed down to keep them cool. Dozens fainted in the heat.

Veiled nuns prayed side by side with young women stripped down to bikinis and youths wearing only shorts.

Most of those present arrived on foot, some walking up to 10km (6 miles) to reach the sprawling Tor Vergata campus.

The pilgrims are holding prayer vigils all night, before the Pope returns in the morning to celebrate Sunday Mass.