Michael Phelps, the professional swimmer from US, is certainly one of the greatest sportsmen and best swimmer in history. At the age of 27, Phelps has won 20 Olympic medals, which made him the most dedicated Olympian of all time.

Among the 20 medals, 16 of them are gold medals. Phelps won 6 gold medals in 2004 Athens Olympics, 8 gold medals in 2008 Beijing Olympics, and 2 gold medals in 2012 London Olympics.