Usain Bolt of Jamaica celebrates winning the men's 4 x 100-meter relay final.
Members of the U.S. team react after winning the gold medal in women's water polo.
The Russian women's team perform their free synchronized swimming routine on their way to garnering a fifth straight gold medal for a country that has dominated this Olympic sport since 2000.
Competitors get some welcome relief from the searing heat while passing through a mist station in the men's 50-kilometer walk.
The referee separates the United States' Jordan Burroughs (left) and Aniuar Geduev (Russia) in the men's freestyle wrestling 74-kilogram quarterfinal. Geduev later went on to win the silver medal.
Nadezhda Glyzina of Russia reacts during during her country's bronze medal match with Hungary in women's water polo. Russia eventually won the medal courtesy of a penalty shootout.
The United States' Paige McPherson (right) grapples with Azerbaijan's Farida Azizova in a preliminary round of the 67-kg women's taekwondo competition.
Dilshod Nazarov of Tajikistan on his way to winning the men's hammer competition. It was his country's first ever gold medal in the Olympics.
Salome Pazhava of Georgia competes using the ball in a preliminary round of the rhythmic gymnastics competition.
Alison Cerutti of Brazil (right) goes up against Paolo Nicolai of Italy during the men's beach volleyball final, which the hosts won 2-0.
Britain's Liam Heath competes in the men's kayak singles competition over 200 meters.
Tianna Bartoletta of the United States on her way to clinching victory in the women's 4 x 100-meter relay race.
David Andersen of Australia (center) is crowded out by the Serbian defense during their men's basketball semifinal. The Serbs eventually triumphed 87-61.
Chong Wei Lee of Malaysia jumps in the air as he celebrates winning against Lin Dan of China in their badminton semifinal match.
Wrestlers Galymzhan Usserbayev of Kazakhstan (top) and Evgheni Nedealco of Moldova compete in qualification for the men's freestyle 74-kilogram competition.
Cyclists in action during the quarterfinal of the men's BMX competition.
U.S. rider McLain Ward takes the water jump at the Olympic Equestrian Center in Deodoro.
Athletes compete during the fencing bonus round in the women's modern pentathlon.