With 22 medals, 18 of them gold, Baltimore swimmer Michael Phelps has brought home more Olympic hardware than any other athlete. Six of those came in 2012 at the London Olympics, where his mixed performance underscored the rarity of Phelps’ achievement at Beijing in 2008, when he won eight golds.

His accomplishments netted him international fame and helped the sport of swimming: USA Swimming has said membership rose 11 percent after the Beijing Olympics, and viewership and attendance of the 2012 Olympic Trials in swimming also jumped dramatically, according to Sports Illustrated.

Phelps has been a force for aquatics off the Olympic podium as well. In 2008, he used his $1 million bonus from sponsor Speedo to establish the Michael Phelps Foundation, an advocacy group that educates kids about swimming, water safety, fitness and character through partners as diverse as the Boys & Girls Clubs and Special Olympics. Phelps’ organization also provides financial grants to talented young athletes to support their training.