A tribesman loyal to the Houthi movement carries his rifle as he leaves a gathering held to show support for the group, in Yemen's capital Sanaa December 15, 2015. (Photo by Khaled Abdullah/Reuters)

Refugees disembark and make their way to a camp at a hotel touted as the world's most northerly ski resort in Riksgransen, Sweden, December 15, 2015. (Photo by Ints Kalnins/Reuters)

People hold out money as butchers sell their remaining produce of the year at discounted prices during the traditional Christmas Eve auction at Smithfield's market in London December 24, 2015. (Photo by Neil Hall/Reuters)

Fireworks light the sky over Copacabana beach during New Year's Eve celebrations in Rio de Janeiro, Brazil, Thursday, January 1, 2016. (Photo by Mauro Pimentel/AP Photo)

A participant runs towards the waters of the North Sea during the annual New Year's plunge event in Ostend, Belgium, January 2, 2016. (Photo by Francois Lenoir/Reuters)

A beauty contestant waits backstage during the final of the annual Miss Tiffany's Universe 2016 transvestite contest in the beach resort town of Pattaya, Thailand, May 13, 2016. (Photo by Athit Perawongmetha/Reuters)

Athlets run during the women's 3000 meter steeplechase at the International Athletics Meeting in Lucerne, Switzerland, 14 June 2016. (Photo by Alexandra Wey/EPA)

A model presents a creation by Givenchy during men's Fashion Week for the Fall/Winter 2017/2018 collection in Paris on January 20, 2017. (Photo by Patrick Kovarik/AFP Photo)