A rare sight in London: Prince William on horseback

Sharp-eyed tourists outside Buckingham Palace had a rare opportunity Saturday to see Prince William on horseback.But even those in the vicinity might well have missed him, since his well-known face was obscured by a traditional tall bearskin hat.The prince was taking part in a rehearsal for next week's "Trooping the Colour," a major event to mark Queen Elizabeth II's official birthday.The queen tu