British Prince William (2nd R), Prince Harry (4th R), and William's wife Katherine (3rd R), Duchess of Cambridge, prepare to board the barge the Spirit of Chartwell during Queen Elizabeth II's Diamond Jubilee Pageant on River Thames in London, Britain, June 3, 2012. The Queen on Sunday took part in the largest event held to celebrate her 60 years as queen by leading a flotilla of boats in a pageant down River Thames through central London. [Xinhua]