In this Tuesday, July 29, 2014, photo, Syrian refugee Samah, 5, poses for a picture at Zaatari refugee camp, near the Syrian border, in Mafraq, Jordan. More than 2.8 million Syrian children inside and outside the country – nearly half the school-aged population – cannot get an education because of the devastation from the civil war, according to the U.N. children's agency, UNICEF. That number is likely higher, as UNICEF can't count the children whose parents didn't register with the United Nations refugee agency. (Photo by Muhammed Muheisen/AP Photo)

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)

Super-cell thunderstorms, whirling tornados and lightning bolts illuminating the sky – these photos capture the terrifying brilliance of American storms. (Photo by Brandon Goforth/Solent News & Photo Agency)

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 Muslim woman wearing a Hijab stands in the waters in the Mediterranean Sea as an Israeli stands nearby on the beach in Tel Aviv, Israel August 21, 2016. (Photo by Baz Ratner/Reuters)

Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)