By Peter Gould BBC News Online correspondent in New York

Thousands watched as Bon Jovi, Alicia Keys and Enrique Iglesias lit up New York's Times Square.

The concert, a prelude to the NFL American football season, was also intended to commemorate the victims of 11 September.

The area around Times Square and 42nd Street became a car-free zone, with a crowd of at least 100,000 people gathering, and NFL estimates as high as 500,000.

An area stretching 20 blocks was closed to motor vehicles, and heavy security was in force with 5,700 police officers deployed and backpacks and bags restricted.

Enrique Iglesias was a crowd-pleaser

But city leaders believe the free show will have given a huge boost to the tourism trade, still recovering after the 11 September attacks.

With its giant advertising displays and Broadway shows, the area around Times Square is famous for its bright lights.

But for the concert it became even more glitzy, with dozens of spotlights trained on a huge open-air stage.

Top of the bill was the band Bon Jovi, with a supporting cast that included Alicia Keys, Eve and Enrique Iglesias.

There was a patriotic finish to the show with Bon Jovi performing America the Beautiful while police officers unfurled a giant US flag across the watching crowd.

City's resilience

"We are trying to find some optimism," said lead singer Jon Bon Jovi, before the concert.

"We want to celebrate the resilience of New York and New Yorkers, and show the world we are grateful for their thoughts and prayers."

It was a sentiment echoed by those in the crowd tonight, among them New Yorker Kyle Gauthier.

Bon Jovi were the main attraction

"Fun is very important to us," he told BBC News Online. "It proves New York is back - back to having a good time.

"We are not afraid of anything, and this restores confidence among Americans."

Lara Mercer from Rhode Island agreed, saying it would send a message to the terrorists:

"It shows that we are strong, and no matter what happens, we are just going to beat them," she said.

Times Square's famous giant video screens showed images of American football players meeting New York police officers and firefighters.

Helicopter journey

There was also a poignant salute to members of the New York Fire Department American football team, the Bravest, which lost players in the September attacks.

At the end of the show, Bon Jovi were taken by helicopter to Giants Stadium, New Jersey to perform at half time.

In the opening game of the new season, the Giants played the San Francisco 49ers, a clash eagerly awaited by fans of American football.

Kyle Gauthier: 'Fun is very important to us'

The NFL is donating millions of dollars to the city, both for redevelopment projects and for ceremonies planned to mark the first anniversary of the terrorist attacks.

Among the rock fans, on holiday from Los Angeles, was Richard Hiskey. He thought the concert was a powerful response to the events of 11 September.

"If something similar had happened in London, and they tied it in with the start of the English Premier League, you can imagine the impact it would have," he said.

"You can't keep New Yorkers down. You may knock us down, but we jump right back up again and kick your ass."

Increased numbers

The authorities in New York may use slightly different language, but they are clearly hoping that this event will send a message to the world that New York is recovering.

Figures released this week show that despite the attacks on the World Trade Center, more Americans visited the city last year than in 2000.

However, they spent significantly less, and there was a drop in the number of international visitors to the city.

After a traumatic year, New Yorkers are letting their hair down

This year, hotel bookings have shown a recovery, but the city still faces huge bills as a result of the devastation of 11 September.

According to a new estimate, the total cost of the terrorist attacks could reach a staggering $95bn.

The destruction of the Twin Towers and surrounding buildings resulted in the loss of 13 million square feet of office space.

Between September 2001 and July 2002, the city lost 83,000 jobs, and there are fears more companies could move out.

"While this devastating event can never be reduced to numbers, it is clear that New York City and the nation will continue to suffer its economic ramifications for years to come," said city comptroller William Thompson.

But on Thursday night, New Yorkers had a party. After a traumatic 12 months, they let their hair down.

Next week, the city will be in more sombre mood, as it joins with the nation in remembering those who lost their lives on 11 September.