U.S. swimmer Michael Phelps, the most decorated Olympian of all time, gestures after winning the 200-meter butterfly on Tuesday, August 9. It was the 20th gold medal of his Olympic career. Later in the night, Phelps <a target="_blank">won his 21st gold</a> -- and his 25th medal in all -- after swimming the anchor leg in the 4x200 freestyle.
U.S. swimmer Michael Phelps, the most decorated Olympian of all time, gestures after winning the 200-meter butterfly on Tuesday, August 9. It was the 20th gold medal of his Olympic career. Later in the night, Phelps won his 21st gold -- and his 25th medal in all -- after swimming the anchor leg in the 4x200 freestyle.
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Phelps' win in the 200-meter butterfly avenged one of the few losses of his Olympic career -- a second-place finish to South Africa's Chad Le Clos in 2012. Le Clos finished fourth in Tuesday's race.
Phelps' win in the 200-meter butterfly avenged one of the few losses of his Olympic career -- a second-place finish to South Africa's Chad Le Clos in 2012. Le Clos finished fourth in Tuesday's race.
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American Katie Ledecky smiles after winning the 200-meter freestyle. It is her second gold in the Rio Games. She also won the 400-meter freestyle.
American Katie Ledecky smiles after winning the 200-meter freestyle. It is her second gold in the Rio Games. She also won the 400-meter freestyle.
Martin Meissner/AP
Ukrainian tennis player Elina Svitolina reacts after <a target="_blank">her third-round victory</a> over top-ranked Serena Williams. Svitolina won 6-4, 6-3.
Ukrainian tennis player Elina Svitolina reacts after her third-round victory over top-ranked Serena Williams. Svitolina won 6-4, 6-3.
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Williams won gold in singles and doubles in the 2012 Olympics. But she is already out of both tournaments in Rio de Janeiro.
Williams won gold in singles and doubles in the 2012 Olympics. But she is already out of both tournaments in Rio de Janeiro.
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U.S. gymnasts -- from left, Gabby Douglas, Madison Kocian, Simone Biles, Aly Raisman and Laurie Hernandez -- celebrate after <a target="_blank">winning the team all-around.</a> The United States also won gold in 2012.
U.S. gymnasts -- from left, Gabby Douglas, Madison Kocian, Simone Biles, Aly Raisman and Laurie Hernandez -- celebrate after winning the team all-around. The United States also won gold in 2012.
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Brazilian basketball player Marcus Marquinhos, in green under the basket, tips in the winning basket to upset Spain 66-65.
Brazilian basketball player Marcus Marquinhos, in green under the basket, tips in the winning basket to upset Spain 66-65.
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Synchronized divers Chen Ruolin and Liu Huixia won the 10-meter platform event for China.
Synchronized divers Chen Ruolin and Liu Huixia won the 10-meter platform event for China.
Matt Dunham/AP
The diving pool, right, <a target="_blank">had turned from blue to green</a> since Monday. The cause is still under investigation, but water tests showed there were no health risks, Rio organizers said.
The diving pool, right, had turned from blue to green since Monday. The cause is still under investigation, but water tests showed there were no health risks, Rio organizers said.
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Egyptian beach volleyball players Doaa Elghobashy and Nada Meawad, left, switch sides with Italy's Marta Menegatti and Laura Giombini.
Egyptian beach volleyball players Doaa Elghobashy and Nada Meawad, left, switch sides with Italy's Marta Menegatti and Laura Giombini.
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Kosovo's Majlinda Kelmendi, right, defeated Italy's Odette Giuffrida in the 52-kilogram (115-pound) judo final. It is <a target="_blank">the first Olympic medal</a> in Kosovo history.
Kosovo's Majlinda Kelmendi, right, defeated Italy's Odette Giuffrida in the 52-kilogram (115-pound) judo final. It is the first Olympic medal in Kosovo history.
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Japanese rugby player Katsuyuki Sakai scores a try against Great Britain.
Japanese rugby player Katsuyuki Sakai scores a try against Great Britain.
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Brazilian rider Ruy Fonseca, on Tom Bombadill Too, hits an obstacle during the jumping round of the team eventing final.
Brazilian rider Ruy Fonseca, on Tom Bombadill Too, hits an obstacle during the jumping round of the team eventing final.
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Australia's Rowie Webster, right, mugs Russia's Anna Timofeeva during a water polo match.
Australia's Rowie Webster, right, mugs Russia's Anna Timofeeva during a water polo match.
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Japanese canoeist Takuya Haneda is congratulated after a ride in the C-1 slalom final. He won the bronze medal.
Japanese canoeist Takuya Haneda is congratulated after a ride in the C-1 slalom final. He won the bronze medal.
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Germany's Sideris Tasiadis competes in the C-1 slalom.
Germany's Sideris Tasiadis competes in the C-1 slalom.
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Mexico's Jorge Alejandro Barajas serves the ball during a volleyball match against France.
Mexico's Jorge Alejandro Barajas serves the ball during a volleyball match against France.
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Italy's volleyball team is introduced before its match against the United States.
Italy's volleyball team is introduced before its match against the United States.
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Iran's Zahra Nemati shoots an arrow during the women's individual archery competition.
Iran's Zahra Nemati shoots an arrow during the women's individual archery competition.
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Hungarian fencer Geza Imre, left, competes against France's Gauthier Grumier during an epee semifinal. Imre won 15-13 to advance to the final, which he lost to South Korea's <br />Park Sang-young.
Hungarian fencer Geza Imre, left, competes against France's Gauthier Grumier during an epee semifinal. Imre won 15-13 to advance to the final, which he lost to South Korea's
Park Sang-young.
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Moldovan weightlifter Serghei Cechir celebrates after finishing in first place in the 69-kilogram (152-pound) weight class. He lifted 144 kilograms (317.5 pounds) in the snatch and 178 kilograms (392.4 pounds) in the clean and jerk for a combined 322 kilograms (709.9 pounds).
Moldovan weightlifter Serghei Cechir celebrates after finishing in first place in the 69-kilogram (152-pound) weight class. He lifted 144 kilograms (317.5 pounds) in the snatch and 178 kilograms (392.4 pounds) in the clean and jerk for a combined 322 kilograms (709.9 pounds).
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The Ivory Coast's Thibault Amani Danho competes in the 100-meter freestyle.
The Ivory Coast's Thibault Amani Danho competes in the 100-meter freestyle.
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Mexico's Misael Uziel Rodriguez, left, takes a battering from Iraq's Waheed Abdulridha Waheed Karaawi during a middleweight boxing match. Rodriguez won the match, however, and advanced.
Mexico's Misael Uziel Rodriguez, left, takes a battering from Iraq's Waheed Abdulridha Waheed Karaawi during a middleweight boxing match. Rodriguez won the match, however, and advanced.
Frank Franklin II/AP
Track cyclists from Great Britain put their heads down during a training session inside the Olympic Velodrome.
Track cyclists from Great Britain put their heads down during a training session inside the Olympic Velodrome.
Patrick Semansky/AP
Zimbabwe's Sean Michael Gunn dives in for a 100-meter freestyle race.
Zimbabwe's Sean Michael Gunn dives in for a 100-meter freestyle race.
Morry Gash/AP
South Korean archer Chang Hye-jin takes part in the women's individual competition. Earlier this week, she and teammates Choi Mi-sun and Ki Bo-bae took gold in the team event.
South Korean archer Chang Hye-jin takes part in the women's individual competition. Earlier this week, she and teammates Choi Mi-sun and Ki Bo-bae took gold in the team event.
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Volleyball player Demian Gonzalez is embraced by Argentina fans after his team beat Russia in a preliminary round. They will next face Poland on Thursday.
Volleyball player Demian Gonzalez is embraced by Argentina fans after his team beat Russia in a preliminary round. They will next face Poland on Thursday.
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