LONDON, ENGLAND - JUNE 30: A member of the military lays a wreath made of roses and bay leaves on the Grave of the Unknown Warrior on behalf of Queen Elizabeth II (2nd L) and Prince Philip, Duke of Edinburgh (L) at a Service on the Eve of the Centenary of the Battle of the Somme at Westminster Abbey on June 30, 2016 in London, United Kingdom. (Photo by Niklas Halle'n - WPA Pool/Getty Images)