Top 10 memories of the London Olympics

Michael Phelps ended his remarkable swimming career by winning four gold and two silver medals in London. He is now the most decorated Olympian ever, with a career total of 22 medals, 18 of them gold. In his final swim, he helped the U.S. reclaim the lead in the 4x100-meter relay, and afterward he got a special trophy from swimming officials that said: "To Michael Phelps, the greatest Olympic athlete of all time."

* United States' swimmer Michael Phelps holds up a silver trophy after being honored as the most decorated Olympian at the Aquatics Centre in the Olympic Park during the 2012 Summer Olympics in London, Saturday, Aug. 4, 2012. Phelps was honored with a special individual ceremony after concluding his record-breaking career Saturday as the most decorated Olympian.