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LONDON, UNITED KINGDOM - JULY 14: Prince Andrew, Duke of York with King Felipe of Spain and Queen Letizia of Spain visit the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia. (Photo by Mark Cuthbert/UK Press via Getty Images)

LONDON, UNITED KINGDOM - JULY 14:  Prince Andrew, Duke of York with King Felipe of Spain and Queen Letizia of Spain visit the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia.  (Photo by Mark Cuthbert/UK Press via Getty Images)

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LONDON, UNITED KINGDOM - JULY 14: Spain's King Felipe VI and Queen Letizia walk through the lobby of the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia. (Photo by Nikias Halle'n - WPA Pool / Getty Images)

LONDON, UNITED KINGDOM - JULY 14:  Spain's King Felipe VI and Queen Letizia walk through the lobby of the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia.  (Photo by Nikias Halle'n - WPA Pool / Getty Images)

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LONDON, UNITED KINGDOM - JULY 14: Spain's King Felipe VI looks through a microscope in a laboratory during the visit to the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia. (Photo by Nikias Halle'n - WPA Pool / Getty Images)

LONDON, UNITED KINGDOM - JULY 14:  Spain's King Felipe VI looks through a microscope in a laboratory during the visit to the Francis Crick Institute during a State visit by the King and Queen of Spain on July 14, 2017 in London. This is the first state visit by the current King Felipe and Queen Letizia, the last being in 1986 with King Juan Carlos and Queen Sofia.  (Photo by Nikias Halle'n - WPA Pool / Getty Images)

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Spain's King Felipe VI (2L) and Queen Letizia (2R) speak to research scientists during their visit to the Francis Crick Institute in central London on July 14, 2017, the third and final day of the Spanish royals' state visit. / AFP PHOTO / POOL / NIKLAS HALLE'N (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)

Spain's King Felipe VI (2L) and Queen Letizia (2R) speak to research scientists during their visit to the Francis Crick Institute in central London on July 14, 2017, the third and final day of the Spanish royals' state visit. / AFP PHOTO / POOL / NIKLAS HALLE'N        (Photo credit should read NIKLAS HALLE'N/AFP/Getty Images)