LONDON For Michael Phelps, the 4x100-meter medley relay was his 18th career gold medal, his last event at the London Games and his final victory lap as an Olympian.
Phelps is retiring at just 27.
His 12-year career as an Olympic star has inspired a new generation in the pool.
The youngest swimmer on the team, 15-year-old Katie Ledecky says Phelps helped pump her up before she earned gold and broke and American record time, set nearly eight years before she was born.
When I walked into the ready room, Michael gave me a high five and wished me good luck and that meant a lot to me, said Ledecky.
While Phelps has inspired fellow athletes with his performance at the games, it was the journey of just getting here that has many in awe of another Olympian from South Africa.
Oscar Pistorius is a runner with no lower legs. Instead, he puts on special blades for the track.
I grew up thinking not that I had a different disability, I grew up thinking I had different shoes, said Pistorius.
After winning an international court battle, he s the first double amputee to compete in the Olympics.
He advanced to the semi-finals Saturday and continues to inspire.
U.S. track star Sanya Richards-Ross has been friends with Pisorius for years.
He s phenomenal. I think he s very determined, really fierce, off the track he s the sweetest guy, said Richards-Ross.
Pistorius isn t expected to medal at the games, but just being allowed to compete may make him one of the biggest winners this Olympics.