A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

A runner in fancy dress participates in the Virgin London Marathon 2013 on April 21, 2013 in London, England. (Photo by Tom Dulat/Getty Images)

Iraqi forces gather during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. (Photo by Reuters/Stringer)

An arctic tern feeds its chick on the Farne Islands off the Northumberland coast, northern England July 8, 2013. The Farne Islands, which lie off the coast of northeast England, are home to a huge array of wildlife. The islands are owned and protected by the British conservation charity, the National Trust, which says they host some 23 species of seabird, as well as a substantial colony of grey seals, who come to have their pups there in the autumn. Every five years the National Trust carries out a census of the islands' population of puffins, and this year's survey showed there were almost 40,000 nesting pairs on the islands – an 8 percent rise from 2008. (Photo by Nigel Roddis/Reuters)

A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)

A street vendor sells sliced fruits during a pro-government rally in Caracas, Venezuela, June 21, 2016. (Photo by Mariana Bazo/Reuters)

A Spanish recortador jumps over a bull during a show in Cali December 21, 2014. (Photo by Jaime Saldarriaga/Reuters)

An Iraqi woman attends a festival commemorating the International Day of Peace in Baghdad, September 21, 2015. (Photo by Thaier al-Sudani/Reuters)