Iraqi Shiite fighters from the Hashed al- Shaabi (Popular Mobilisation) paramilitaries hold a position near the village of Tal Abtah, south of Tal Afar, on November 30, 2016, during a broad offencive by Iraq forces to retake the city Mosul from Islamic State group jihadists. (Photo by Ahmad Al- Rubaye/AFP Photo)

The Sugar Plum Fairy, Katherine Free, left, dances with the dog, Pig, during the Birmingham's Ballet “Mutt-cracker”, a rendition of the famous ballet “The Nutcracker”, in Birmingham, Alabama, December 8, 2016. (Photo by Brynn Anderson/AP Photo)

A horse- drawn carriage rides along the race course through the Thuringian Forest in Oberhof, Germany, 05 January 2017. Winter found its way to Saxony, Saxony- Anhalt, and Thuringia. In some regions it can get as low as negative 20 degrees overnight. (Photo by Martin Schutt/Zentralbild/DPA)

Rapper Pitbull performs onstage during Nickelodeon's celebration of the new Burbank facility on January 11, 2017 in Los Angeles, California. (Photo by Charley Gallay/Getty Images for Nickelodeon)

A man performs a split as he practices Kung Fu at Beihai Park in Beijing, China August 20, 2017. (Photo by Reuters/China Stringer Network)

A member of the Air Force's Wings of Blue Parachute Demonstration Team salutes as he jumps out of an aircraft, during the opening ceremony of Aviation Nation 2017 Nellis Air and Space Expo at Nellis Air Force Base, Nev., November 10, 2017. (Photo by Senior Airman Kevin Tanenbaum/Reuters/U.S. Air Force)

Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

A dancer performs as visitors take pictures at an auto show in Tianjin, China April 28, 2016. (Photo by Reuters/Stringer)