Amanda Ashe of Oakland, left, faces off with a police officer during the second night of demonstrations in Emeryville, California, following the grand jury decision in the shooting of Michael Brown in Ferguson, Missouri, November 25, 2014. (Photo by Elijah Nouvelage/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 wear skull masks during an anti government protest, as Chile's President Michelle Bachelet delivers a speech inside the National Congress, in Valparaiso city, Chile May 21, 2016. (Photo by Ivan Alvarado/Reuters)

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)

An activist in a Guy Fawkes mask adjusts a skull and crossbones flag during a demonstration against the Anti-Counterfeiting Trade Agreement (ACTA) on February 25, 2012 in Berlin, Germany. (Photo by Adam Berry/Getty Images)

A student runs for cover as riot police clash with students during a demonstration on February 29, 2012 in Barcelona, Spain. Student associations have called upon 120,000 students to strike in protest against education cuts recently announced by the Catalan government. (Photo by David Ramos/Getty Images)

A demonstrator waves Turkey's national flag as he sits on a monument during a protest against Turkey's Prime Minister Tayyip Erdogan and his ruling AK Party in central Ankara June 2, 2013. Erdogan accused Turkey's main secular opposition party on Sunday of stirring a wave of anti-government protests, as tens of thousands regrouped in Istanbul and Ankara after a lull and trouble flared again in the capital. Police used tear gas on protesters in Ankara but the clashes were relatively minor compared with major violence in Turkey's biggest cities on the previous two days. (Photo by Umit Bektas/Reuters)