LONDON, UNITED KINGDOM - AUGUST 30: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince William, Duke of Cambridge and Prince Harry view tributes to Diana, Princess of Wales left at the gates of Kensington Palace after visiting the Sunken Garden on August 30, 2017 in London, England. The Sunken Garden has been transformed into a White Garden dedicated to Diana, Princess of Wales mother of The Duke of Cambridge and Prince Harry marking the 20th anniversary of her death. (Photo by Max Mumby/Indigo/Getty Images)