Hundreds of thousands of people are gathering to line London's streets as athletes, including distance runner Mo Farah and heptathlete Jessica Ennis, are honored for leading Britain to its most successful Olympic showing in 104 years.
Twenty-one floats will carry members of the Olympic and Paralympic teams from east London to Buckingham Palace.
The parade also will be a celebration of Britain staging two events that overcame anxiety about security concerns and inclement weather to provide a lift for the recession-hit nation.
Britain's summer in the international spotlight began in May with festivities to mark the Queen's Diamond Jubilee.
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