“Red Arrows” at the 2016 royal air tattoo, RAF Fairford, UK. By Jonny Williams, finalist: action. (Photo by Jonny Williams/UK National Geographic Traveller Photography Competition 2018)

Some two thousand runners dressed as Santa Claus make their way through Clapham Common during The London Santa Dash, to raise money for Great Ormond Street Hospital, in London, Britain December 4, 2016. (Photo by Dylan Martinez/Reuters)

A model presents a creation by Spanish designer Agatha Ruiz de la Prada during the Mercedes Benz Fashion Week Madrid, MBFWM, in Madrid, Spain, 16 September 2016. The MBFWM runs from 15 to 20 September 2016. (Photo by J.J. Guillen/EPA)

Russia's Ekaterina Birlova casts a shadow on the sand as she serves to Poland during a women's beach volleyball match at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Tuesday, August 9, 2016. (Photo by Marcio Jose Sanchez/AP Photo)

(L-R) Miss Universe 2015 Pia Wurtzbach, Miss USA 2015 Olivia Jordan and Miss Teen USA 2015 Katherine Haik attend the 2016 Miss USA pageant at T-Mobile Arena on June 5, 2016 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)

A U.S. Marine kneels beside a Multi-Utility Tactical Transport ( MUTT) during a patrol as part of Rim of the Pacific (RIMPAC) 2016 an exercise held at Camp Pendleton, California United States, July 13, 2016. (Photo by Mike Blake/Reuters)

A dog groomer prepares a model dog during the 2nd Annual Shenzhen International Pet Exhibition, July 14, 2016, in Shenzhen, China. The pet exhibition runs from July 14 - 17, 2016 at the Shenzhen Convention & Exhibition Center. (Photo by VCG/Getty Images)

Ukrainian teenagers hit each other with pillows during a large pillow fight in downtown Kiev, Ukraine, 24 April 2016. About hundred people took part in the event “Pillow battle 2016” in Kiev. (Photo by Roman Pilipey/EPA)