A simulated casualty is evacuated during an emergency services exercise at the disused Aldwych underground station on February 22, 2012 in London, England. Operation Forward Defensive aims to test the response to a terrorist incident on the London Underground network during the 2012 Olympic Games. (Photo by Peter Macdiarmid/Getty Images)

Two Girls who managed to evade the police walk away as police on foot and horseback push back to te curd at Park Row, In New York on April 26, 1960, A milling throng of more than 1,000 High students who storned city hall in a Demonstration supporting teachers wage demands. (Photo by AP Photo)

Police spraying protesters with pepper spray inside Central Station after a Black Lives Matter rally in Sydney, Australia, 06 June 2020, a protest against the deaths of Aboriginal people in custody and solidarity with the US protests for George Floyd. (Photo by James Gourley/EPA/EFE)

Police officers speak to a woman in Greenwich Park in London, England on April 4, 2020. The Government has announced a lockdown to slow the spread of Coronavirus and reduce pressure on the NHS. (Photo by Alamy Live News)

Elvis Presley impersonator Sean Wright poses next to the Elvis Express train at Sydney's Central station before it departs for the 26th annual Elvis Festival being held in the New South Wales town of Parkes in Australia, January 11, 2018. (Photo by Daniel Munoz/Reuters)

People sit on the top of a truck heavily piled with corn-stalks plies as they head for Mogadishu from Afgooye on October 19, 2016. At least four police officers were killed on October 18 when a suicide bomb attacker rammed an explosives-packed car into a police station before fighters from the Al-Qaeda-linked Shabaab group subsequently stormed the area killing at least 10 people, including soldiers and civilians. (Photo by Mohamed Abdiwahab/AFP Photo)

A masked man in military fatigues brings a blindfolded Irma Krat, arrested and held by pro-Russian protestors before her meeting with journalists near of occupied police station in Slaviansk, Ukraine, 21 April 2014. Pro-Russian activists are demanding broader autonomy from Kiev and closer ties to Russia. Pro-Russian activists continued occupying government, police and other administrative buildings in eastern Ukrainian cities, in defiance of an ultimatum by the Ukrainian government to lay down their weapons. Russia, the United States, the European Union and Ukraine on 17 April had agreed on steps to de-escalate the crisis in Ukraine during talks in Geneva, Switzerland. (Photo by Roman Pilipey/EPA)

U.S. Park Police work to keep people away from the area surrounding the Washington Monument after a 5.8 magnitude earthquake struck the east coast August 23, 2011 in Washington, DC. Police officers said that unidentified material had fallen off the Washington Monument as a result of the earthquake. All the monuments and buildings along the National Mall have been evacuated and closed. (Photo by Chip Somodevilla/Getty Images)