LONDON, UNITED KINGDOM - AUGUST 02: (EMBARGOED FOR PUBLICATION IN UK NEWSPAPERS UNTIL 48 HOURS AFTER CREATE DATE AND TIME) Prince Philip, Duke of Edinburgh (in his role as Captain General, Royal Marines) attends the The Captain General's Parade to mark the finale of the 1664 Global Challenge at Buckingham Palace on August 2, 2017 in London, England. The Captain General's Parade is Prince Philip's last official engagement before retiring from carrying out solo Royal engagements. (Photo by Max Mumby/Indigo/Getty Images)