Former U.S. President Barack Obama congratulates U.S. President Donald Trump after he took the oath of office on the West Front of the U.S. Capitol on Jan. 20, 2017 in Washington, DC. (Chip Somodevilla/Getty Images)
Russian President Vladimir Putin (R) meets with Britain's Prime Minister Theresa May on the sidelines of the G20 Leaders Summit in Hangzhou on September 4, 2016. / AFP / SPUTNIK / ALEXEI DRUZHININ (Photo credit should read ALEXEI DRUZHININ/AFP/Getty Images)
Chinese President Xi Jinping speaks at the opening session of the 19th Communist Party Congress in Beijing on Oct. 18, 2017. (Kevin Frayer/Getty Images)
French President Emmanuel Macron attends a ceremony at the Royal Military Academy Sandhurst, west of London on Jan. 18. (Ludovic Marin/AFP/Getty Images)