Michael Phelps is participating in his fifth Summer Games, a U.S. record among male swimmers. He’s already won 23 medals, including a record-setting 19 golds — including a gold with the 4×100-meter freestyle relay team Sunday night — and could add three more in Rio when he competes in the 
100-meter butterfly, the 200-meter butterfly, and the 200-meter individual medley.
And winning an individual Olympic medal in a swimming event at the age of 31 years old might be even more impressive than racking up that record-setting medal count. Phelps turned 31 in June, which makes him super old in terms of competitive swimming.