American swimmer Michael Phelps is one of the Olympic athletes who has rewritten the record books. He has won 22 Olympic medals in total and is the most decorated Olympian of all time after collecting his remarkable haul at three different Olympiads so far.
Phelps success has spiralled him into the media as the stuff of living legend so you can count on enormous attention on him at the Aquatics Centre. He will want to increase his mountains of medals to put as much distance between himself and any newcomers and secure his place in swimming history.
Find out more about some of the other stars ahead of the Olympics: