A tribal fighter loyal to Yemen's government stands in Al Khurais village of Nihm district east of the capital Sanaa January 11, 2016. (Photo by Ali Owidha/Reuters)
Emily Ratajkowski filming DKNY commercial on January 20, 2017 in New York City, USA. The 25-year-old model braved the freezing New York temperatures as she wore just a black lace bra and matching French knickers, with a pair of clumpy biker boots. (Photo by Startraks Photo/Rex Features/Shutterstock)
Students training to be flight attendants hold books on their heads, chopsticks in their mouths, and papers in between their knees, as they take part in a standing posture practice at a vocational school in Shijiazhuang, Hebei province, China May 4, 2017. (Photo by Reuters/Stringer)
Runners sleep before competing in the 2016 New York City Marathon in the Manhattan borough of New York City, NY, U.S. November 6, 2016. (Photo by Eduardo Munoz/Reuters)
Kendall Jenner seen at Universal, NBC, Focus Features, E! Entertainment Golden Globes After Party Sponsored by Chrysler on Sunday, January 8, 2017, in Beverly Hills, Calif. (Photo by Eric Charbonneau/Invision for Focus Features/AP Images)