Anti-government protesters stand with makeshift shields made from traffic signs next to a barricade in Kiev January 24, 2014
Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 "Occupy Central" civil disobedience movement in Hong Kong September 27, 2014
Protesters shield themselves from police water cannon during a May Day demonstration in Istanbul May 1, 2014
Riot police use a water cannon to disperse anti-government protesters near the Middle East Technical University (ODTU) in Ankara, Turkey, March 11, 2014
A Palestinian uses a sling to throw back a tear gas canister fired by Israeli troops during clashes in the West Bank city of Bethlehem October 14, 2015
A demonstrator holds a street sign to shield himself as he stands amidst a cloud of tear gas during a protest against the government of President Nicolas Maduro in Caracas, February 22, 2014
A protester uses a tennis racket to return a tear gas canister during a demonstration to protest the government's proposed labor law reforms in Nantes, France, June 2, 2016
A protester hits a teargas canister back at riot police with a hockey stick on the second day of protests against the third Summit of the Americas, in Quebec City, Quebec, Canada, April 21, 2001