USA: Michael Phelps
USA swimming star Michael Phelps shows off one of his eight gold medals at Beijing 2008.
Place of birth: Baltimore, USA
Previous Olympics: 3
Previous medals: 16
There are a million and one reasons why Michael Phelps has become arguably the greatest Olympian of all time.
For a start, there are his physical attributes - at 1.93 metres tall with US size 14 feet, ankle and knee joints that are more flexible than most ballet dancers' and an armspan of 2.01m he's as close to the 'perfect' stature for swimming as you are likely to get.
The American also follows a punishing training regime that apparently sees him swim nearly 80 kilometres per week. Then there is the remarkable will to win that has spurred him on to every major title available - including 16 Olympic and 34 World Championships medals.
But for all his physical, genetic and mental qualities, the man himself attributes a big part of his success to something else - his coach Bob Bowman.
Bowman has been a key part of Phelps' life ever since he was 11 years old, when the pair first began working together at the North Baltimore Aquatic Club.
As a child, Phelps used swimming as something of a distraction. His parents divorced when he was nine and when he was in sixth grade he was diagnosed with Attention Deficit Hyperactivity Disorder (ADHD), a condition that means sufferers struggle to concentrate on simple tasks and appear hyperactive in their behaviour.
Under Bowman's guidance, the talented but troubled youngster gradually developed, qualifying for his first Olympics at Sydney 2000 and becoming the youngest male to make the US Olympic swimming team in 68 years.
It was the start of a remarkable career that has seen him become not just the biggest name in the sport of swimming but one of the most famous athletes in the world.
He has, though, never forgotten the debt that he owes to Bowman. "I guess he saw something in me," Phelps once told USA Today. "He's been able to help me grow from the little 11-year-old swimmer who didn't really know what he was doing to the person I am today."
The two have now worked together for more than 15 years, sometimes falling out but more often that not working in perfect harmony, with Bowman's strict attention to detail combining perfectly with Phelps' natural gifts. And nowhere was their partnership demonstrated more effectively than at Beijing 2008, where the American became the most successful Olympian ever at a single Games by winning eight gold medals.
His performances in the Water Cube in Beijing were simply breathtaking, as he broke seven world records and surpassed the landmark set by countryman and fellow swimmer Mark Spitz at Munich 1972.
After the first of his medals, in the 400m individual medley, he cried as he stood on the podium. Up in the stands, Bowman cried too. It was a rare show of emotion from them both, but four years on any sign of sentiment has disappeared.
Rather than sitting back and admiring their achievements, the pair refocused and targeted even more success.
Gradually, their attention turned towards London and Phelps has admitted that while his exploits in China are likely to be his legacy, the chance to try and make more history was too good to turn down.
But with the XXX Olympiad more than likely to be his last, London 2012 seems set to mark the final chapter in the story of one of the most successful partnerships in sport.