Armed Yemeni children sit in the back of a pick up truck with fighters loyal to Yemen's Saudi-backed President Abedrabbo Mansour Hadi in the Dar saad neighbourhood of the southern Yemeni city of Aden on May 10, 2015, as they continue to battle Shiite Huthi rebels. (Photo by Saleh Al-Obeidi/AFP Photo)

Miss Colombia 2015 Ariadna Gutierrez rehearses for the upcoming Miss Universe telecast while at Planet Hollywood Resort and Casino in Las Vegas, Nevada, December 12. 2015. (Photo by Darren Decker/Reuters/The Miss Universe Organization)

Visitors dressed in superhero costumes attend the Paris Comics Expo at the Parc Floral in Paris, France, April 15, 2016. (Photo by Charles Platiau/Reuters)

A little girl takes a picture of a lion in the zoo in Frankfurt, Germany, Tuesday, September 13, 2016. (Photo by Michael Probst/AP Photo)

Meghan Puhr participates in a virtual realty presentation during an Intel news conference before CES International, Wednesday, January 4, 2017, in Las Vegas. (Photo by John Locher/AP Photo)

A traffic police woman whistles at a pedestrian, Monday, July 27, 2015, in Pyongyang, North Korea where its citizens are having a one-day national holiday to celebrate the country's 62nd anniversary of the armistice that ended the Korean War. (Photo by Wong Maye-E/AP Photo)