A partial solar eclipse is seen in a break in the clouds during rush hour in downtown Wichita Kan., Thursday, October 23, 2014. A partial eclipse occurs when the moon covers a portion of the sun as seen from the Earth. (AP Photo/The Wichita Eagle, Travis Heying)

A baby rhesus macaque (Macaca mulatta) looks up as it plays with a tiger cub at a zoo in Hefei, Anhui province, August 2, 2012. (Photo by Jianan Yu/Reuters)

Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Hillary Clinton waves to a selfie-taking crowd at a recent campaign event in Orlando, Florida on September 26, 2016. (Photo by Barbara Kinney/Hillary for America)

Students are seen on a pickup truck at the agricultural road which leads to the capital city of Cairo, Egypt, October 13, 2016. (Photo by Amr Abdallah Dalsh/Reuters)

North Korean traffic police women chat next to a residential building while off duty Tuesday, October 18, 2016, in Pyongyang, North Korea. (Photo by Wong Maye-E/AP Photo)

A light railway train passes through a residential building on March 18, 2017 in Chongqing, China. Chongqing Rail Transit No.2 and a 19-storey residential building have been built across each other. The railway set its Liziba Station on the sixth to eighth floor in the building with noise reduction equipment. (Photo by VCG/VCG via Getty Images)

Iraqi soldiers from 9th Armoured Division give drops of water to a dehydrated child rescued earlier by soldiers at the frontline, during the ongoing fighting between Iraqi forces and Islamic State militants near the Old City in western Mosul, Iraq June 13, 2017. (Photo by Erik De Castro/Reuters)