LONDON, ENGLAND - MARCH 5:  Queen Elizabeth II (2L) bids farewell to Mexican President Enrique Pena Nieto (2R) and Mexico's First Lady Angelica Rivera as Prince Philip, Duke of Edinburgh (L) looks on at Buckingham Palace on March 5, 2015 in London, England. Today is the final day of the Mexican President's visit to the UK and he will travel to Aberdeen to meet senior representatives of the gas and oil industry.  (Photo by Jonathan Brady - WPA Pool/Getty Images)