Britain's Queen Elizabeth and Prince Philip laugh after bidding farewell to the President of Ireland Michael D. Higgins and his wife Sabina at Windsor Castle in Windsor, southern England April 11, 2014. The Irish President and his wife Sabina left Windsor at the end of a four day State Visit to Britain, during which they stayed at Windsor Castle as guests of Queen Elizabeth. REUTERS/Leon Neal/Pool (BRITAIN - Tags: ENTERTAINMENT SOCIETY ROYALS)