Cameron van der Burgh of South Africa celebrates his gold medal in the men's 100m breaststroke. He later admitted that he took extra dolphin kicks during his swim, a violation of the rules. Adam Pretty/Getty Images hide caption

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American sprinter Allyson Felix leads the field on her way to winning the women's 200 meters gold medal in London's Olympic Stadium. Quinn Rooney/Getty Images hide caption

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American Dana Vollmer celebrates after her gold medal win Sunday in the women's 100-meter butterfly swimming final at the Aquatics Centre in the Olympic Park. Matt Slocum/AP hide caption

itoggle caption Matt Slocum/AP