London: Cyclists and swimmers take centre stage at the London Olympics on Saturday, hoping to match the drama of a kaleidoscopic opening ceremony dedicated to inspiring a new generation of athletes. (Agencies)
Fittingly, the most decorated Olympian of all, Michael Phelps, seeks to add to his 14 gold medals of the last two Games in a titanic clash with fellow American Ryan Lochte in the pool.
Cycling world champion Mark Cavendish aims to set the host nation on the way to its best ever Games with victory in the men's road race.
Britain's Queen Elizabeth declared the Olympics open after playing a cameo role in an opening ceremony designed to highlight the grandeur and eccentricities of the nation that invented modern sport.
"In a sense the Olympic Games are coming home tonight," International Olympic Committee (IOC) president Jacques Rogge told a crowd of 60,000 in the stadium and a television audience of perhaps a billion more.
"This great, sports-loving country is widely recognised as the birthplace of modern sport."
The ceremony provided a spectacular and often surreal sweep through three centuries of British achievement in science, social reform and the arts, each generation inspired by and building on the achievements of the last.
The 86-year-old queen, marking her Diamond Jubilee this year, put aside royal reserve in a video where she stepped on to a helicopter with James Bond actor Daniel Craig to be carried aloft from Buckingham Palace.
A film clip showed doubles of her and Bond skydiving towards the stadium and, moments later, she made her entrance in person. It was a moment of rare informality from a figure revered for her devotion to duty and sense of continuity rather than her common touch.
Having pledged to present a democratic image of the Olympics, it was appropriate that Oscar-winning film director Danny Boyle should shun celebrities for the lighting of the cauldron that will burn for the duration of the Games.
Media speculation was feverish about which sporting hero would get the honour but instead, in keeping with the ceremony's theme of "Inspire a Generation", seven British Olympic greats passed the flame to seven unknown teenage athletes.
They in turn lit a spectacular arrangement of more than 200 copper 'petals' representing the participating countries, which rose up in the centre of the stadium to converge into a powerfully symbolic single cauldron.
More than 10,000 athletes from 204 countries will compete in 26 sports over 17 days of competition in the only city to have staged the modern Games three times.
The first medals will be won in the women's 10 metres air rifle. But the biggest event of the first day is in the pool where Phelps defends his 400 metres individual medley title against Lochte.
Phelps, winner of a record eight gold medals at the Beijing Games four years ago, will become the first man to capture three consecutive Olympic swimming titles in the same discipline if he succeeds.
However, Lochte finished first in the U.S. trials this year and has exuded confidence this week.
"I know this is going to be my year," he said. "All the training I have put in is going to pay off. I know it.
"I just know I am ready. I am not going for silver or bronze. I am going for gold."
Phelps is to retire after these Games but the seven events he is competing in will give him ample scope to gather the three medals of any colour he needs to overtake Soviet gymnast Larisa Latynina's record haul of 18.
He was relaxed and affable during his media commitments this week although still fiercely competitive.
"I'm more emotional because these will be the last competitive moments of my career," he said. "Once I get into the pool I won't be holding back."
Sprint specialist Cavendish was the only member of the all-conquering British cycling team who failed to win a medal in Beijing.
But this time he has the expert support of four elite competitors, including his country's first Tour de France champion, and the backing of a British public inspired by the success of the riders to take part in competitive and leisure cycling as never before.
Six days after his triumph in France, Bradley Wiggins will devote his efforts to helping Cavendish win the 156-mile (250-km) circuit to the south of London, beginning and ending outside Buckingham Palace.
He will be assisted by Chris Froome, second in the Tour, fellow stage winner David Millar and British champion Ian Stannard.
"There's only Ian who didn't win a stage," Wiggins said. "We are all quite humble about our achievements but externally we must look an incredibly dominant force. It's no secret that Cav wants to win but he's got four incredible guys to help him."
The British tactics are also no secret to their rivals. The support riders will try to ensure Cavendish does not trail the leaders by too big a margin on the steep Box Hill, which must be climbed nine times, so that he can chase and overtake them on the way down.
The fact he will be a marked man adds to the pressure on Cavendish of being expected to secure his first Olympic gold and Britain's first of the Games.
"An Olympic medal, regardless if it's the first or last on offer, is an Olympic medal for your team," he said.
"It's easy to get emotional about it - I've been nervous this week. We've trained to be able to deal with those nerves and we've got to put it to bed."
London: Cyclists and swimmers take centre stage at the London Olympics on Saturday, hoping to match the drama of a kaleidoscopic opening ceremony dedicated to inspiring a new generation of athletes.