BEIJING, Aug 24 (Reuters) - International Olympic Committee President Jacques Rogge declared the "truly exceptional" Beijing Games closed on Sunday.

"You have shown us the unifying power of sport," he told competitors packed in to the National Stadium.

"The Olympic spirit lives in the warm embrace of competitive rivals from nations in conflict. Keep that spirit alive when you return home.

"And now, in accordance with tradition, I declare the Games of the XXIX Olympiad closed, and I call upon the youth of the world to assemble four years from now in London to celebrate the Games of the XXX Olympiad."

With the declaration, the show began.

Spanish tenor, a British soccer star and a throng of kung-fu fighters are among the scheduled closing-ceremony attractions tonight as China concludes its first Olympics and hands over the role of Summer Games to London.

Fireworks are planned to burst at 18 locations across the vast city, delighting its denizens and also a packed house of more than 90,000 in the National Stadium, or the Bird's Nest.

Tonight's closing ceremony has been designed to be more lighthearted than the opening ceremony Aug. 8, which focused heavily on Chinese history.

Highlights for the closing include a duet by tenor Placido Domingo and Chinese soprano Song Zuying, as well as a display by several hundred kung fu practitioners from a martial arts school.

"It's going to be very different from the opening ceremony, which was burdened with heavy responsibility to show Chinese culture to the world," one of the directors, Miao Pei, told China's Southern Metropolis News.

Film director Zhang Yimou, in charge of both the opening and closing ceremonies, said the dramatic highlight of the finale will be the extinguishing of the Olympic flame atop the stadium.

London, host of the 2012 Olympics, took over part way through the ceremony for an eight-minute show that featured a red double-decker London bus driving into the stadium and converting into a stage.

Led Zeppelin guitarist Jimmy Page and British singing sensation Leona Lewis performed, while soccer icon David Beckham kicked a ball into a crowd of onlookers.

The British were celebrating not only London's upcoming role as host, but also a breakthrough performance here in China by British athletes, completing their country's best Olympics in a century.

"We will not compete with the (Chinese) ceremony," said London 2012 organizer Bill Morris. "It will be simple, youthful, athletic, loud and proud like London, entertaining and fun."

British Prime Minister Gordon Brown and London's mayor, Boris Johnson, received the Olympic flag from Beijing Mayor Guo Jinlong.

China invested more than $40 billion in the games, which it viewed as a chance to show the world its dramatic economic progress.

It was certainly worth all the effort as the communist giant also clinched first place in the gold medal standings (with 51 gold) in Olympic history. It also marked its debut as a world superpower in sports.