HAVANA, CUBA - MARCH 21: Cuban President Raul Castro (L) poses for a photograph with U.S. first lady Michelle Obama and U.S. President Barack Obama before a state dinner at the Palace of the Revolution March 21, 2016 in Havana, Cuba. March 21, 2016 in Havana, Cuba. This is the first time a sitting U.S. president has visited Cuba in 88 years. (Photo by Chip Somodevilla/Getty Images)

HAVANA, CUBA - MARCH 21:  Cuban President Raul Castro (L) poses for a photograph with U.S. first lady Michelle Obama and U.S. President Barack Obama before a state dinner at the Palace of the Revolution March 21, 2016 in Havana, Cuba. March 21, 2016 in Havana, Cuba. This is the first time a sitting U.S. president has visited Cuba in 88 years.  (Photo by Chip Somodevilla/Getty Images)