Michael Phelps

Phelps first took to the pool at the age of 7 and was undoubtedly influenced by his two elder sisters, including Whitney, who competed at the U.S. Olympic trials in 1996. At 15 he was the youngest male American since 1932 to take part in the Olympics, where he finished a very respectable fifth in the 200 butterfly. Just a year later he bagged his first world championship gold in the 200 butterfly, adding another three golds in the 200 and 400 medley and the 4x100 medley. The 6-foot-4 Baltimore native won three gold and two silver medals breaking five world records in the process.

Now, at just 23 years old, Phelps has won eight gold medals in Beijing and become the most successful single-Games Olympian of all time. He is also the most decorated gold medalist in Olympic history with 14 career gold medals.