The Americans are dominating the gym and claiming the swimming pools in Rio. Michael Phelps and the Final Five put on a show on Day Four of the Olympics.

Simone Biles and the rest of the US Women's Gymnastic team spent some time thinking about their nickname. They said they would unveil it at the right time. Minutes after defending their gold medal in the team competition by a massive margin, they looked into the NBC cameras and said, "We are the Final Five."

Why did they choose the "Final Five?" This is Márta Károlyi's last group of gymnasts working with Team USA. She and her husband, Béla, changed the entire landscape of gymnastics in the USA, and this group marked the end of an era.


The Americans were crushing the competition so hard, all Biles had to do was complete her floor routine to ensure the gold medal for her team. She did a lot more than that.

Biles is already getting talked about as one of the greatest athletes in the history of US Women's Gymnastics, and she will have a chance to prove that with a ton of individual events coming up at Rio. She executes maneuvers other gymnasts wouldn't even try, and she makes it look easy.

If you missed Biles' floor routine, this is how Team USA sealed the deal. She does things human beings shouldn't be physically capable of.

Pure insanity. The only thing better than her moves is her smile, and she never stopped grinning from ear to ear all night long.

While the Final Five handled business in the gym, Katie Ladecky and Michael Phelps dyed the pools red, white and blue.

Ladecky won gold in the 200m Freestyle, which isn't even her best stroke, and then Phelps picked up two more gold medals in the 200m Butterfly and the 4x200m relay. Ladecky put her rivalry to bed earlier this week, and Phelps did the same on Day Four.

Phelps now owns 21 gold medals (25 total), but there was something even sweeter about his victory in Rio. He got to share it with his baby boy, Boomer. You can hear Phelps getting choked up with NBC's Michelle Tafoya after his race.

Whenever he retires from international competition, he will be remembered as the greatest individual athlete in Olympic history. Over the course of five different Olympic games, Phelps dominated the water. Maybe years down the line, his son Boomer can follow in Dad's massive, flipper-like footsteps.

Team USA has a stranglehold on the medal count in Rio. Not only do the Americans have the most medals (by a lot), they have the most golds too. With athletes like Phelps, Ladecky and Biles, it should come as no surprise.

This is probably the final chapter in Phelps' epic Olympic story, but it's just the beginning for Ladecky, Biles and a lot of others. By the end of Rio 2016, we will know the future of American Olympic greatness. Don't miss history.

(Photo by Laurence Griffiths/Getty Images)