Prince William, right, and Camilla, the Duchess of Cornwall, leave Buckingham Palace in a horse-drawn carriage during the Trooping The Colour, a military parade held to mark the monarch's official birthday, on June 13, 2009, in London.
Queen Rania Al Abdullah of Jordan, left, and Queen Silvia of Sweden ride in a carriage to a welcoming ceremony at the Swedish Royal Palace on Oct. 7, 2003, in Stockholm.
PICTURES: Queen Rania
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The Emperor Akihito and Empress Michiko of Japan arrive to a welcoming ceremony in a carriage, where they were greeted by Right Honourable Michaelle Jean, then-Governor General of Canada, and husband Jean-Daniel Lafond at Rideau Hall on July 6, 2009, in Ottawa.
Thobeka Mabiba Zuma, the wife of South African President Jacob Zuma, leaves by carriage following the ceremonial welcome on Horse
Guards Parade on March 3, 2010, in London.
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Danish Crown Prince Frederik and his bride Crown Princess Mary Shoot Hoops wave from their carriage during a procession from Copenhagen Cathedral to Amalienborg Palace after their wedding ceremony on May 14, 2004, in Copenhagen, Denmark.
Princess Beatrice, right, and Princess Eugenie, daughters of Britain's Duchess of York Sarah Ferguson, ride a carriage down The Mall in front of Buckingham Palace during the Trooping The Colour parade on June 12, 2010, in London.
Dutch Queen Beatrix, left, Crown Prince William Alexander and Princess Maxima (behind the Queen) ride in the Golden Carriage from Noordeinde Palace to the Knights Hall on Sept. 16, 2008, in The Hague, South Holland.