An undercover police officer, who had been marching with anti-police demonstrators, aims his gun at protesters after some in the crowd attacked him and his partner in Oakland, California December 10, 2014. Police said more than 100 demonstrators marched in Berkeley, California, which has a history of social activism. Under cloudy skies, turnout was smaller than earlier in the week, when demonstrators in the area threw rocks at police and shut down a major freeway. (Photo by Noah Berger/Reuters)

A police officer carries a woman who fainted while gathering to try to buy pasta outside a supermarket in Caracas, Venezuela, June 10, 2016. (Photo by Carlos Garcia Rawlins/Reuters)

Civil security aircrafts parade during the inauguration of the Nimes-Garons civil security air force base on March 10, 2017 in Nimes, southern France. (Photo by Pascal Guyot/AFP Photo)

Ahmed, a 10-year-old jockey, looks on during the opening of the International Camel Racing festival at the Sarabium desert in Ismailia, Egypt, March 21, 2017. (Photo by Amr Abdallah Dalsh/Reuters)

Hindu priests wash the head of a buffalo calf which was sacrificed as part of a ritual at a temple during the Durga Puja festival in Agartala, India, October 10, 2016. (Photo by Jayanta Dey/Reuters)

US Vogue’s top fashion editor works with photographers to inject style with sci-fi and fantasy. A new book, “Stoppers: Photographs from My Life at Vogue” by Phyllis Posnick and Vogue’s chief editor, Anna Wintour, highlights the results. Here: Surburban Woman #10, Mountainville, New York, August 2006. (Photo by Steven Klein)

Orin Larsen of Inglis, Manitoba hangs on to the horse Dancing Queen in the Bareback event during the Calgary Stampede rodeo in Calgary, Alberta, July 10, 2015. (Photo by Todd Korol/Reuters)

A girl walks past a destroyed mosque in the town of Mararaba, after the Nigerian military recaptured it from Boko Haram, in Adamawa state May 10, 2015. (Photo by Akintunde Akinleye/Reuters)