A demonstrator is carried away by plain-clothes police during a march against government reforms and cost-cutting measures in Brussels , October 7, 2015. (Photo by Francois Lenoir/Reuters)

A pro-abortion activist wearing a poncho with an illustration of a woman in jail, demonstrates to demand the decriminalization of abortion in Mexico City, Mexico September 28, 2016. (Photo by Carlos Jasso/Reuters)

A riot policeman watches as a police vehicle burns in Braamfontein, Johannesburg, South Africa, Tuesday, October 25, 2016. Rioters in South Africa set a police vehicle on fire Tuesday and stoned vehicles near a Johannesburg university that has been the scene of sometimes violent protests by students demanding free education. The violence broke out in streets near the University of the Witwatersrand at around the same time that student protesters met and marched off the campus, South African media reported. (Photo by Yeshiel Panchia/AP Photo)

A hooded protester throws a petrol bomb to riot policemen during clashes, following a rally marking the 43rd anniversary of a 1973 student uprising against the military dictatorship that was ruling Greece, in Athens, Greece, November 17, 2016. (Photo by Yannis Behrakis/Reuters)

A protester wearing high heels during a demonstration to support International Day for the Elimination of Violence Against Women in Santiago, Chile, November 25, 2016. (Photo by Pablo Sanhueza/Reuters)

In this Thursday, December 1, 2016 photo, Cat Bigney, part of the Oglala Native American tribe, waits on the shore of the Cannonball river for travelers to arrive by canoe at the Oceti Sakowin camp where people have gathered to protest the Dakota Access oil pipeline in Cannon Ball, N.D. So far, those at the camp have shrugged off the heavy snow, icy winds and frigid temperatures. But if they defy next week's government deadline to abandon the camp, demonstrators know the real deep freeze lies ahead. Life-threatening wind chills and towering snow drifts could mean the greatest challenge is simple survival. (Photo by David Goldman/AP Photo)

Demonstrators protest the shooting death of Alton Sterling near the headquarters of the Baton Rouge Police Department in Baton Rouge, Louisiana, U.S. July 9, 2016. (Photo by Jonathan Bachman/Reuters)

Riot police fire tear gas during a protest by supporters of Dilma Rousseff in Sao Paulo, Brazil August 31, 2016. (Photo by Paulo Whitaker/Reuters)