A young man, who says he is part of a local criminal gang, poses for a picture holding a gun in the neighbourhood of Korogcho in Nairobi, Kenya, March 19, 2015. Around 2 million people live in the shantytowns packed in around Kenya's capital. Crime is high amid chronic unemployment levels, while basic services and sanitation are scarce. Residents try to make the best of things, eking out a living and picking up work where they can. (Photo by Siegfried Modola/Reuters)

Men help a woman affected by tear gas used by National Police officers to disperse a demonstration of supporters of Fanmi Lavalas political party in the streets of Port-au-Prince, Haiti, November 22, 2016. (Photo by Andres Martinez Casares/Reuters)

Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

British comedian and director Charles Chaplin (1889–1977) and actress Paulette Goddard (1911–1990), to whom he was married for seven years, star in the comedy “Modern Times”, directed by Chaplin himself. (Photo by Hulton Archive/Getty Images). 1936

A .44 Colt Dragon with a traditional Cowboy's hat. This weapon was originally used in the Mexican War of 1846-8 and it is typical of the type used in the “Wild West” of America. (Photo by Orlando /Three Lions/Getty Images). Circa 1950

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

To draw the public's attention to a new line of bathing suits, a Tokyo department store used live models to show off the suits on June 5, 1950. The rain didn't bother the curious, and both the girls and the crowd seemed to like the idea of staring at each other through the glass. (Photo by AP Photo via The Atlantic)

A bear that wandered into a University of Colorado Boulder dorm complex falls from a tree after being tranquilized by Colorado wildlife officials on April 26, 2012. Colorado wildlife official Jennifer Churchill said that the 200-pound male bear was tagged and relocated to a remote Rocky Mountain area. The bear was hit by two cars on May 3 and died. (Photo by Andy Duann)