Michael Phelps PHOTOS: A Look At The Swimming Icon's Olympic Career In Pictures

Michael Phelps, of the United States, smiles with his gold medal after setting a world record in the 400-meter individual medley at the Olympic Aquatic Centre during the 2004 Olympic Games in Athens.

-- Michael Phelps heads into retirement the only way imaginable – with an 18th Olympic gold medal.

Since his Olympic debut as a 15-year-old in Sydney a dozen years ago, Phelps has won twice as many golds as any other Olympian. His total of 22 medals is easily the best mark, too.

Phelps capped off a mind-boggling career with a victory in the 4x100-meter medley relay Saturday.

Here's a look back at Phelps' Olympic career in photos:

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