Seven promising young British athletes lit the Olympic cauldron early Saturday, capping the Games' festive opening ceremony in east London.

The torch, which minutes earlier had been on a boat driven by football star David Beckham down the River Thames, had been carried into the stadium by five-time Olympic gold medalist Steve Redgrave.

The retired rower then passed it to the young athletes, who lit part of the outer rim of the torch, setting off a domino effect as fire methodically engulfed the cauldron. The small flames eventually rose and converged into the sky at the stadium.

A short time earlier, Queen Elizabeth II formally pronounced the Olympics open for business, saying, "I declare open the Games of London, celebrating the 30th Olympiad of the modern era."

Organizers had said they expected 1 billion people worldwide to watch the opening ceremony -- which was created by Danny Boyle, best known for directing the Oscar-winning film"Slumdog Millionaire" -- on television.

Tens of thousands more congregated in "fan zones" around the British capital to watch the festivities on big screens, their enthusiasm hardly diminished by overcast sky and sporadic showers.

The event opened with a scene dubbed "Green and Pleasant," after a line from poet William Blake. It featured an idyllic view of a British countryside. Rolling hills, fields and rivers -- complete with picnicking families, sports being played on a village green and farmyard animals -- made up the elaborate set.

Hundreds of volunteers dressed in period costumes walked, danced and otherwise performed as music played. The set soon transformed into one featuring factories, recalling the Industrial Revolution, including large smokestacks emerging from below.

After a short film featuring Daniel Craig, the latest actor to play cinematic British spy James Bond, and none other than Queen Elizabeth II herself, the next performance paid tribute to Britain's National Health Service and children's literature.

J.K. Rowling, author of the best-selling Harry Potter books, kicked off the scene -- which featured, among others, the evil Voldemort from her series and magical nanny Mary Poppins.

Next came a performance of the iconic song from "Chariots of Fire," a tale about two British Olympians from 1924 that was lightened up by slapstick comedian Mr. Bean. Then came a showcase for pop songs from the Beatles to the Rolling Stones to Frankie Goes to Hollywood to David Bowie, which was followed by a short live performance by rapper Dizzee Rascal.

There was also a special shout-out toTim Berners-Lee, a London native who is credited with inventing the World Wide Web. His words, "This is for everyone" at one point lit up a part of the stands for all to see.

Just over one hour in, the Olympic athletes finally made their way into the stadium led, per tradition, by the Greek delegation.

That was followed by another performance featuring bicyclists with glowing butterfly wings going around the stadium, one of whom soared into the air.

Several dignitaries escorted the Olympic flag as it entered the stadium, among them U.N. Secretary-General Ban Ki-moonand legendary American boxer Muhammad Ali.

Sebastian Coe, chairman of the London Games organizing committee and a four-time Olympic medalist, then promised, "London 2012 will inspire a generation."

"In the next two weeks, we will show all that has made London one of the greatest cities in the world," Coe said. "Let us determine all of us, all over the world, that London 2012 will see the very best of us."

International Olympic Committee chief Jacques Rogge noted the history being made with these Games -- the first competition in which every delegation had female athletes and the first time any city has hosted the Olympics three times.

"In a sense, the Olympic Games are coming home tonight," he said.

Excitement has been brewing in and around London for years, and it's been especially palpable in recent days.