Protestors affiliated with the Occupy Wall Street movement block the entrance to the Iowa Democratic Party headquarters during a protest on December 29, 2011 in Des Moines, Iowa. Thirteen people were arrested during the protest. (Photo by Andrew Burton/Getty Images)

A policewoman tries to stop an anti-Occupy protester from breaking a police cordon to charge at pro-democracy protesters during a confrontation in Hong Kong October 13, 2014. Hundreds of unidentified people, some wearing masks, tried to break down protest barriers in the heart of Hong Kong's business district on Monday, scuffling with protesters who have occupied the streets for the past two weeks. (Photo by Bobby Yip/Reuters)

Protesters clad in improvised protective gear prepare for a clash with police in central Kiev, Ukraine, Monday, January 20, 2014. After a night of vicious streets battles, anti-government protesters and police clashed anew Monday in the Ukrainian capital Kiev. (Photo by Evgeny Feldman/AP Photo)

Police officers take cover as they clash with protesters after an officer shot and killed a black man in Brooklyn Center, Minneapolis, Minnesota on April 11,2021. Protests broke out April 11, 2021 night after US police fatally shot a young Black man in a suburb of Minneapolis – where a former police officer is currently on trial for the murder of George Floyd. Hundreds of people gathered outside the police station in Brooklyn Center, northwest of Minneapolis. Police fired teargas and flash bangs at the demonstrators, according to an AFP videojournalist at the scene. (Photo by Kerem Yucel/AFP Photo)

Paint splattered police officers look on during clashes outside Top Shop on Oxford Street, during marches in protest at government cuts on March 26, 2011 in London, England. Thousands are taking part in the Trades Union Congress (TUC) organised march to Hyde Park where a rally will take place. Police say they are deploying 4500 officers. (Photo by Dan Kitwood/Getty Images)

Rio de Janeiro's state military policemen aim their guns during a violent protest in a favela next to Copacabana, Rio de Janeiro on April 22, 2014. Violent protests broke out in Rio's landmark beachfront district, Copacabana, following the death of a resident last weekend during clashes with the Army in a nearby favela. (Photo by Christophe Simon/AFP Photo)

People react following the verdict in the trial of former Minneapolis police officer Derek Chauvin, found guilty of the death of George Floyd, at BLM Plaza in Washington, D.C., U.S., April 20, 2021. (Photo by Evelyn Hockstein/Reuters)

A demonstrator reacts during a rally following the death in Minneapolis police custody of George Floyd, in Boston, Massachusetts, U.S., June 2, 2020. (Photo by Brian Snyder/Reuters)