Members of the media film as a ranger performs a post mortem on the carcass of a rhino after it was killed for its horn by poachers at the Kruger national park in Mpumalanga province August 27, 2014. Rhino poachers in South Africa now risk giving themselves away when they shoot thanks to a high-tech, gunfire-detection system being piloted in the country's flagship Kruger National Park. The stakes are high, for rhinos are being slain in escalating numbers for their prized horns, alarming both conservationists and the government since wildlife in South Africa is an important tourist draw. (Photo by Siphiwe Sibeko/Reuters)

An attendee dances at the start of the “Big Goth Dance Party” during the Porcupine Freedom Festival, or PorcFest, the Free State Project's annual summer gathering in Lancaster, NH on Wednesday, June 25, 2014. (Photo by Matthew Cavanaugh/The Washington Post)

A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

Chantel Sydnor participates in the annual Sturgis Motorcycle Rally in Sturgis, South Dakota, August 4, 2015. This year marks the 75th anniversary of the rally expected to draw hundreds of thousands of motorcycle enthusiasts from around the world for events throughout the week-long festival, according to organizers. (Photo by Kristina Barker/Reuters)

Japan's delegation gather to sign the formal surrender document on the U.S. Navy battleship USS Missouri in Tokyo Bay in a September 2, 1945 file photo. (Photo by Reuters/US Navy)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)

British fashion model Twiggy plays around on the bumper cars at the Bertram Mills Circus in London, England on January 10, 1967. (Photo by AP Photo)

Italian actress Zaina Dridi walks the red carpet for “Carol” during the 10th Rome Film Fest at Auditorium Parco Della Musica on October 22, 2015 in Rome, Italy. (Photo by PA Press Association Images)