Michael Fred Phelps II (born June 30, 1985 in Baltimore, Maryland) is an American swimmer, a world-record holder and the winningnest Olympian in history.

Michael Phelps (at the age of 15) first appeared at the 2000 Summer Olympics in Sydney as the youngest American male swimmer at an Olympic Games in 68 years. While he did not win a medal, he was fifth in the 200 m Butterfly, Phelps proceeded to make a name for himself in swimming shortly thereafter. Five months after the Sydney Olympics, Phelps broke the world record in the 200 m butterfly to become, at 15 years and 9 months, the youngest man ever to set a swimming world record. He then broke his own record again at the World Championships in Fukuoka, Japan (1:54.58). At the 2002 Summer Nationals in Fort Lauderdale, Phelps also broke the world record for the 400 m individual medley and set American marks in the 100 m butterfly and the 200 m individual medley.

In 2004, Phelps broke his own world record in the 400 m individual medley (4:09.09) and in June, he broke the world record in the 200 m individual medley (1:56.04). Then on July 7, 2007, Phelps broke his own world record again in the 400 m individual medley (4:08.41) during the U.S. trials for the 2004 Summer Olympics.

And on August 13, 2008, Phelps became the winningnest Olympian in history by having won 11 Olympic gold medals in his career.