Jamaica's Usain Bolt finishes first in his men's 100m round 1 heats. -Photo by Reuters

Gold medallist Serena Williams of the U.S. poses after winning the women's singles gold medal match against Russia's Maria Sharapova. -Photo by Reuters

France's Sandrine Gruda (L) shoots past Russia's Natalya Vieru. -Photo by Reuters

Britain's Mohamed Farah (front) celebrates in front of US' Galen Rupp (L) as he wins the men's 10,000m final. -Photo by AP

Michael Phelps of the U.S. swims the butterfly leg of the men's 4x100m medley relay final. -Photo by Reuters

Michael Phelps of the U.S. smiles as he holds up his award recognising him as the most decorated Olympian. -Photo by Reuters

An ariel performer flies and slams a dunk during halftime of a women's basketball game between Russia and France. -Photo by AP

Britain's Jessica Ennis gestures to the crowd before receiving her gold medal for the heptathlon during the athletics in the Olympic Stadium. -Photo by AP