American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)

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)

Police, bystanders and soldiers aid a fallen soldier at the War Memorial as police respond to an apparent terrorist attack on October 22, 2014 in Ottawa, Canada. A gunman is believed to have shot a soldier as he was standing guard at the National War Memorial in Ottawa. It is believed police then chased the man into the main parliament building at Parliament Hill, where more shots were fired. (Photo by Wayne Cuddington/Postmedia/Barcroft Media/ABACAPress)

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

Looters scramble in Philipsburg, St. Maarten, Sunday September 10, 1995 for goods in the Ram's department store, which contained mostly food and liquor. No attempts are currently being made by Dutch troops on the island to stop the looting, since few relief supplies have arrived in St. Maarten, which was ravaged on Tuesday by Hurricane Luis. (Photo by John McConnico/AP Photo)

A woman poses for a photograph in front of a 3D painting at HK 3D Museum in Hong Kong June 26, 2014. (Photo by Tyrone Siu/Reuters)

A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)

A protester jumps on the table in front of the European Central Bank President Mario Draghi during a news conference in Frankfurt, Germany April 15, 2015. (Photo by Kai Pfaffenbach/Reuters)