A police officer stands at a police cordon near the scene of a terror attack in London, U.K., on Sunday, June 4, 2017. A van swerved into Saturday-night crowds on London Bridge, before three men got out and went on a stabbing rampage through nearby bars. (Photo by Luke MacGregor/Bloomberg)

Police haul a youth to the paddy wagon as an undetermined number of arrest were made in downtown Atlanta, Georgia, February 25, 1971, as police moved in to disperse black youths after windows were broken and rocks and fruit thrown in what officers called “a major disturbance”. (Photo by Charles Kelly/AP Photo)

Children residents take a selfie as they wait for the police to dance, an unconventional approach to connect the police with the community in rough neighbourhoods, as part of the “Tirando Barrio” (Marking territory) programme in Saltillo, Northern Mexico September 9, 2016. T-Shirt reads “Street Dancers”. (Photo by Daniel Becerril/Reuters)

Two Girls who managed to evade the police walk away as police on foot and horseback push back to te curd at Park Row, In New York on April 26, 1960, A milling throng of more than 1,000 High students who storned city hall in a Demonstration supporting teachers wage demands. (Photo by AP Photo)

Northeastern girls getting commando training at the Delhi Police Training Centre, Jharoda Kalan on September 4, 2017 in New Delhi, India. For the first time ever, Delhi Police are providing commando training to 40 young women from the Northeast. Once the commando training is over, these girls will be a part of the «Parakram Vans», an initiative taken by Delhi Police against terrorism. (Photo by Manoj Verma/Hindustan Times via Getty Images)

Model presents a creation from the Amir Slama collection during Sao Paulo Fashion Week in Sao Paulo, Brazil August 30, 2017. (Photo by Paulo Whitaker/Reuters)

The Epson International Pano awards showcase the work of the best panoramic photographers from around the world. Here: “Paepalanthus at Moonlight” Veadeiros Tablelands, Brazil. (Photo by Marcio Cabral/Epson International Pano Awards 2017)

Brazilian navy soldiers watch a woman as they patrol the area at the Copacabana Beach before carnival festivities in Rio de Janeiro, Brazil February 14, 2017. (Photo by Sergio Moraes/Reuters)