WINDSOR, ENGLAND - MAY 15:  Lady Louise Windsor rides a horse during Queen Elizabeth II's 90th Birthday Celebrations at Home Park, Windsor on May 15, 2016 in Windsor, England.The show has run over four nights to celebrate the Queen turning 90. The show features 1,500 performers, 900 horses and tells the story of the life of the Queen. Members of the Royal Family have attend the show each night and the Queen will attend on the last evening  (Photo by Ben A. Pruchnie/Getty Images)