U.S. Air Force wounded warrior, Capt. Sarah Evans, jumps rope in a gym in San Antonio, Texas. Evans was diagnosed with cancer while deployed to Afghanistan and was medically evacuated back to the United States where her leg was amputated. (Photo by Master Sgt. Jeffrey Allen/U.S. Air Force)

Pete McLeod of Canada flies in formation with Nigel Lamb of Great Britain, Martin Sonka of the Czech Republic and Kirby Chambliss of the United States during a Recon flight prior to the seventh stage of the Red Bull Air Race World Championship over the Hoover Dam on October 09, 2014 on the border between the U.S. states of Arizona and Nevada. (Photo by Joerg Mitter/Red Bull via Getty Images)

The Elf on the Shelf balloon floats down Sixth Avenue during the 88th Annual Macy's Thanksgiving Day Parade in New York November 27, 2014. (Photo by Andrew Kelly/Reuters)

For France, the trauma of the Algerian War (1954-1962) was not unlike the experience of the Vietnam War for the United States. But, unlike the conflict in Vietnam, few photographic documents exist from that period in Algeria: it is as if the French responded with collective amnesia. Marc Garanger’s Algerian Women is one of the few photographic essays dedicated to that painful period... Photo: A 1960 photograph of an Algerian woman in a French regroupment village. (Photo by Marc Garanger)

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)

Trevor Olson, from Minnesota, dressed as the character “Joker”, poses for a photograph at New York's Comic Con convention, October 9, 2014, in New York City. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields in Javits Center. (Photo by Shannon Stapleton/Reuters)

Models Bria Murphy and Shayne Murphy attend the BET AWARDS '14 at Nokia Theatre L.A. LIVE on June 29, 2014 in Los Angeles, California. (Photo by Earl Gibson III/Getty Images for BET)

Rihanna celebrates by flashing the crowd on July 13, 2014 in Rio de Janeiro, Brazil. (Photo by Twitter.com)