On Day 8 of Olympic competition, Michael Phelps nabbed gold one last time and Usain Bolt began his chase for an unprecedented achievement.
Here are four of the biggest Things to Watch during the Summer Games Saturday.
1) Phelps Finishes Strong
Michael Phelps came up with the perfect goodbye — if it was one.
He won his 23rd Olympic gold medal Saturday night by swimming his best stroke, the butterfly, in the 4x100 medley.
If he retires, as he insists he is, despite joshing about it from teammate Ryan Murphy in a post-swim interview, he leaves behind a singular legacy. It is, simply, this: Phelps has won more Olympic events than any other athlete has medaled in.
How to watch: See a reply of Phelps' final swim (and win) online here.
2) Usain Bold Ready to Seek Unprecedented Win
Usain Bolt had an easy win in his 100-meter heat Saturday. The crowd went wild for his entrance but he calmed them by putting his fingers to his lips for silence just before the race. He moves on to the semifinals Sunday.
Bolt, the fastest man alive and defending gold medalist in the 100m, 200m and 4x100, is looking to add to his immense gold stockpile as he competes in the men's 100-meter preliminary rounds.
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Bolt will attempt to accomplish an unprecedented "Triple-Triple" by becoming the first athlete to win all three titles at three consecutive games. He's certainly not lacking for confidence.
"I'll win all three gold (medals)," he told CNN. "There's never anything else for me when it comes to a championship."
3) Ibtihaj Muhammad Battles Her Way to a Bronze
U.S. fencer Ibtihaj Muhammad made Rio history as the first American athlete to wear a hijab during the Olympics. Although she was defeated in individual sabre earlier in the games, Muhammad helped garner a bronze in team sabre Saturday.
The U.S. team had beaten Poland 45-43, in the quarterfinals, but they lost to Russia 45-42, in the semi-finals, sending them to the bronze bout against Italy.
Muhammad added 10 points before she was switched out for alternate Monica Aksamit, who contributed 5. The women defeated Italy 45-30.
How to watch: See video from the win on your smartphone, tablet or desktop computer.
4) Men's Volleyball Team Keeps Hope Alive
Team USA defeated with France Saturday in a preliminary men's volleyball match, strengthening the Americans' chances of reaching the quarterfinals.
Earlier this week, the U.S. men came back from the brink of being eliminated. They'd suffered two losses in two matches, but defeated Brazil -- considered to be the best team in the world -- on Thursday to stay in the fight.
The big-time win over Brazil netted the Americans three points, but that only put them in a tie with Canada for the final quarterfinal qualifying position. They helped out their chances of reaching the knockout round against France, beating them 25-22, 25-22, 14-25, 25-22.
They also hope Canada falters along the way.