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)

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)

Activists and supporters of Ukrainian nationalist groups light flares during a rally to mark the third anniversary of the Euromaidan Revolution in downtown Kiev, Ukraine, 21 November 2016. About one thousand activists took park in the rally during which they burned tires on the Independence Square, destroyed the Russian bank Sberbank and broke windows in the office of a Ukrainian politician Viktor Medvedchuk, according to Ukrainian media. (Photo by Roman Pilipey/EPA)

A man lights up his cigarette with the flames of a bus burned by anti-government demonstrators during a protest against the constitutional amendment PEC 55, which limits public spending, in front of Brazil's National Congress in Brasilia, Brazil December 13, 2016. (Photo by Adriano Machado/Reuters)

A Venezuelan Bolivarian National Police officer fires tear gas towards demonstrators during a protest in Caracas, Venezuela, Monday, April 10, 2017. Thousands of people in Venezuela's capital are protesting against the government of President Nicolas Maduro, demanding new elections and vowing to stay in the streets during the usually quiet Easter Week. (Photo by Fernando Llano/AP Photo)

A detained protester escapes from a police truck after riot police released teargas to disperse the #OccupyHarambeeAve demonstration in Kenya's capital Nairobi November 25, 2014. Kenyan police used teargas to disperse demonstrators shouting “President, Stop the killings!” outside President Uhuru Kenyatta's offices on Tuesday, in the protest over 28 people killed in a weekend attack claimed by Islamist militants. (Photo by Thomas Mukoya/Reuters)

US President George W. Bush (R) and Russian President Vladimir Putin wave as the two presidents go for a ride in Putin's 1956 Volga before dinner 08 May 2005 at the his residence outside of Moscow. Bush hailed Russia's “bravery and sacrifice” in defeating Nazism, as he met Putin ahead of ceremonies marking the 60th anniversary of the end of World War II. Bush, who the previous day criticized the decades-long Soviet occupation of central Europe, said he was looking forward to the 09 May ceremony on Moscow's Red Square, to be attended by over 50 national leaders. (Photo by Tim Sloan/AFP Photo)