CAMBRIDGE, UNITED KINGDOM - JULY 13: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince William, Duke of Cambridge gives his grandparents Queen Elizabeth II and Prince Philip, Duke of Edinburgh a tour of his air ambulance helicopter as they open the new East Anglian Air Ambulance base at Cambridge Airport on July 13, 2016 in Cambridge, England. (Photo by Max Mumby/Indigo/Getty Images)
