A Bedouin rifleman hides behind his camel while he carefully takes aim in the Sahara desert. (Photo by Three Lions/Getty Images). Circa 1955

A simulated casualty is evacuated during an emergency services exercise at the disused Aldwych underground station on February 22, 2012 in London, England. Operation Forward Defensive aims to test the response to a terrorist incident on the London Underground network during the 2012 Olympic Games. (Photo by Peter Macdiarmid/Getty Images)

A young couple rest in a football field after a forest fire devastated Santa Olga, 240 kilometres south of Santiago, on January 26, 2017. Six people – among them four firefighters and two police – have now been killed battling vast forest fires in central Chile, officials said Wednesday. Multiple blazes have ravaged 238,000 hectares (588,000 acres) and are growing, the National Forestry Corporation said in a statement. (Photo by Pablo Vera Lisperguer/AFP Photo)

In this Feb. 17, 2017 photo, surfers walk to La Pampilla beach in Lima, Peru. Night surfing apparently came about in Lima because of a dispute with the capital municipality that in 2015 increased the width of a road that runs along the coast. The surfers protested the construction for months by camping on the asphalted beach area, but in the end the municipality prevailed, with support from the police. At the end of 2016, perhaps to win over the surfers, Lima's mayor set up beach lights that allows for night surfing. (Photo by Rodrigo Abd/AP Photo)

A Femen activist is led away by French police in Henin-beaumont, northern France, Sunday, May 7, 2017. Voters across France are choosing a new president in an unusually tense and important election that could decide Europe's future, making a stark choice between pro-business progressive candidate Emmanuel Macron and far-right populist Marine Le Pen. (Photo by Francois Mori/AP Photo)

Participants of an unauthorized opposition rally gather in Tverskaya street in central Moscow on June 12, 2017. Authorities detained Russian opposition politician Alexei Navalny and hundreds of his supporters on Monday, as they mounted demonstrations across the nation against government corruption. Over 200 were detained in Moscow and Saint Petersburg an hour into the protest, according to an NGO that tracks arrests, with Navalny himself picked up by police in his building as he was headed to the event. (Photo by Vasily Maximov/AFP Photo)

A Flemish demonstrator, one of thousands who gathered for a march through Brussels to protest against what the Flemings call their subjucation by the French-speaking Walloons, draws back as he is jeered by a crowd of Walloons on the pavement in a Brussels Street, on October 14, 1962. The Flemish demonstrators clashed with Walloon counter demonstrators as riot police sought to maintain order. The Flemings claim that although they form 60% of the population in Belgium, they are inadequately represented in the government, and they say, the Walloons get most of the top jobs in the armed forces and the diplomatic service. (Photo by AP Photo)