President Barack Obama

Britain's Prince Philip, Duke of Edinbur...Britain's Prince Philip, Duke of Edinburgh (L) drives US President Barack Obama (2L), US First Lady Michelle Obama (2R) and Britain's Queen Elizabeth II (R) from the helicopter into Windsor Castle after the Obama's arrived for a private lunch in Windsor, southern England, on April, 22, 2016.  / AFP PHOTO / POOL / GEOFF PUGHGEOFF PUGH/AFP/Getty Images

Geoff Pugh/AFP/Getty

Britain’s Prince Philip, Duke of Edinburgh drives US President Barack Obama, US First Lady Michelle Obama and Britain’s Queen Elizabeth II from the helicopter into Windsor Castle after the Obama’s arrived for a private lunch in Windsor, southern England 

US President Barack Obama walks on the stage to speak on education at University of Buffalo, the State University of New York, on August 22, 2013 in Buffalo, New York. Obama is on a two-day bus tour through New York and Pennsylvania to discuss his plan to make college more affordable, tackle rising costs, and improve value for students and their families.

Jewel Samad/AFP

US President Barack Obama walks on stage to talk about education at University at Buffalo, the State University of New York, on Thursday in Buffalo, New York. Mr Obama is on a two-day bus tour through New York and Pennsylvania to discuss his plan to make college more affordable, tackle rising costs, and improve value for students and their families