View of an American marine as he lies in a foxhole and whistles at a husky, one of the scouting dogs used during the landing on Guam, August 1944. (Photo by W. Eugene Smith/Time & Life Pictures/Getty Images)

A young woman employee of North American Aviation Incorporated, working over the landing gear mechanism of a P-51 fighter plane, Inglewood, California, 1942. (Photo by Alfred T. Palmer/Buyenlarge/Getty Images)

Pamukkale, Turkey, is home to these terrace pools, formed by the build-up of carbonate mineral from the warm water flowing from the thermal springs above. (Photo by Image Courtesy of Jennifer Hayes/Getty Images)

St Mary's Cathedral is illuminated as part of a Christmas lights display in celebration of Christmas on December 19, 2014 in Sydney, Australia. (Photo by Brendon Thorne/Getty Images)

People with his face covered in oil and soot and carrying bull horns representing a devil join a carnival festival on February 14, 2015 in Luzon, Spain. (Photo by David Ramos/Getty Images)

Actress Brittany Snow takes a selfie with a fan at The 2015 MTV Movie Awards at Nokia Theatre L.A. Live on April 12, 2015 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)

Amal Clooney attends the “Money Monster” premiere during the 69th annual Cannes Film Festival at the Palais des Festivals on May 12, 2016 in Cannes, France. (Photo by Andreas Rentz/Getty Images)

Models pose backstage ahead of the Zhivago show at Mercedes-Benz Fashion Week Resort 17 Collections at Carriageworks on May 16, 2016 in Sydney, Australia. (Photo by Mark Nolan/Getty Images)