Culinary Specialist 2nd Class Jaqueline Rodriguez subdues a simulated suspect after being sprayed with oleoresin capsicum (OC) spray during security training aboard the amphibious dock landing ship USS Comstock (LSD 45). (U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac/Released). May 10, 2011

Children attend a war safety awareness class conducted by civil defence members, in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria May 14, 2016. (Photo by Khalil Ashawi/Reuters)

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

Interpolitex - the largest national forum of homeland security is the only national security fair of federal status and importance. It is held to provide manufacturers, suppliers and users special equipment and weaponry with an efficient tool for implementing a wide range of advertising and marketing objectives, monitoring of the market and deal-making. (Russia, Moscow, October 2011)

A helicopter pours water over a wildfire with the Space Shuttle Endeavour seen through heavy smoke in the background April 27, 2011 in Cape Canaveral, Florida. (Photo by Roberto Gonzalez/Getty Images)

Kaci Nuyen 8, holds a “Kiddizoom Twist” camera during a Hamleys Christmas toy photocall at Hamleys Toy store on June 28, 2011 in London, England. The famous toy store unveiled today their “must have” toys for Christmas 2011. (Photo by Dan Kitwood/Getty Images)

Student protestors, including one girl with a camera, struggle with soldiers from the Chinese Army, the PLA. Tiananmen Square, 1989. (Photo by Jeff Widener/Associated Press)

A “Free Syrian Army” fighter in the Bustan Pasha neighborhood of Aleppo, Syria, August 21, 2013. (Photo by James Lawler Duggan)