A stream of athletes carried the hopes of their nations over the Olympic threshold into the greatest adventure of their sporting lives.

Others, lesser known and untried, nurtured dreams of glory that may never bear fruit.

Whatever their background and aspirations, the flag bearers walking proudly in Friday's opening ceremony will never forget the thrill of leading their national team on to the biggest stage of them all.

Although there were gold medallists and world champions in the massed ranks behind them, fame was not the key to their selection.

American basketballer Dawn Staley was one of those basking in the occasion, a veteran of the 1996 and 2000 gold medal-winning U.S. women's team.

"Carrying the flag is a ray of hope," said the 34-year-old, who has set up a foundation to help youngsters in the Philadelphia neighbourhoods where she grew up.

"A little girl from the housing projects of North Philly is leading the U.S. team into the Olympic Games. It's bigger than any basketball game I've ever played.

"I'm not an emotional person but this makes me emotional," she told her Charlotte Sting team website.

China, Asia's main medal hopes, walked taller than anyone -- behind NBA basketball player Yao Ming. At 2.26 metres, he is the tallest athlete to compete in a Games.

The U.S. team was not the only one deciding their flag-bearer by a vote of athletes and team captains as the Games returned to their birthplace in the cradle of democracy. British athletes selected judoka Kate Howey.

Australia, who expected more than half of their 480 athletes to skip the ceremony, were led by 44-year-old yachtsman Colin Beashel who has come out of retirement to compete in what will be his sixth Games.

Greece, stepping into the full Olympic glare just as a drug-testing debacle threatened the future of national track hero Costas Kenteris, placed their national pride on the powerful shoulders of weightlifter Pyrros Dimas.

The three times Olympic champion, now 33 and dubbed 'miracleman' after a series of comebacks, is seeking a record fourth successive weightlifting gold.

Malaysia had the shortest, youngest and lightest man -- Bryan Nickson Lomas, a 14-year-old diver named after former Manchester United and England captain Bryan Robson.

"We had two reasons for picking Bryan for the job," Malaysia's chef de mission Mani Jegathesan said.

"One, we want the medal prospects to be focused on getting up on the podium and not carrying the flag. But more importantly, we wanted to make a strong statement of our confidence in our young people."