Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)

Comedians and cast members from the Pleasance's 2016 programme bounce on yellow spacehoppers in costume at Calton Hill on August 15, 2016 in Edinburgh, Scotland. The Pleasance and Waverley Care are marking a twenty five years in partnership, it's a unique relationship that helps raise awareness and challenges the stigma that continues to be attached to HIV and Hepatitis C and has raised more than £375,000 so far. (Photo by Jeff J. Mitchell/Getty Images)

Tourists photograph a red dear stag visiting a car park near Glen Coe on December 1, 2017 in Glen Coe,Scotland. On the first day of the meteorological calendar, the UK was experiencing slightly warmer temperatures today with weather forecasters indicating that the recent cold spell is almost over. Yesterday's snow across eastern parts of England is expected to melt away over the course Friday as temperatures start to rise. (Photo by Jeff J. Mitchell/Getty Images)

Luling, Louisiana, US. New evidence contradicts previous claims of the relative safety of glyphosate, the world’s most widely used herbicide, which is manufactured here. It is often used in conjunction with seeds that have been genetically modified to tolerate its application, meaning that anyone consuming these crops is eating a genetically modified plant, and whatever residue of the pesticide that remains. (Photo by J. Henry Fair/Industrial Scars/Papadakis Publisher)

New York Islanders' Matt Martin (17) and Pittsburgh Penguins' Zach Aston-Reese (12) fight during the second period in Game 2 of an NHL hockey Stanley Cup first-round playoff series in Pittsburgh, Tuesday, May 18, 2021. Both players received a two-minute minor penalty. (Photo by Gene J. Puskar/AP Photo)

Students from St Andrew's University indulge in a tradition of covering themselves with foam to honour the “academic family” on October 20, 2014, in St Andrews, Scotland. Every November the “raisin weekend” which is held in the university's Lower College Lawn, is celebrated and a gift of raisins (now foam) is traditionally given by first year students to their elders as a thank you for their guidance and in exchange they receive a receipt in Latin. (Photo by Jeff J. Mitchell/Getty Images)

Supporters of US President Donald J. Trump gather for a rally in Freedom Plaza to protest Congress's upcoming certification of Joe Biden as the next president in Washington, DC, USA, 05 January 2021. Various groups of Trump supporters announced rallies on 06 January 2021 as Congress meets to certify the results of the 2020 US Presidential election. (Photo by Shawn Thew/EPA/EFE)

Groundhog Club co-handler Al Dereume holds Punxsutawney Phil, the weather prognosticating groundhog, in front of the crowd gathered for the 133rd celebration of Groundhog Day on Gobbler's Knob in Punxsutawney, Pa. Saturday, February 2, 2019. Phil's handlers said that the groundhog has forecast an early spring. (Photo by Gene J. Puskar/AP Photo)