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)

Members of a teenage girl gang convincing an unwilling recruit to join the gang, circa 1955. (Photo by Vecchio/Three Lions)

A teenager reacts as she receives a shot of the Sinovac vaccine for COVID-19 during a vaccination campaign at a school in Denpasar, Bali, Indonesia on Monday, July 5, 2021. (Photo by Firdia Lisnawati/AP Photo)

In this March 18, 2015 photo, Andrea, better known as Loira, which is the Portuguese word for “blonde”, poses for a portrait in an open-air crack cocaine market, known as a “cracolandia” or crackland where users can buy crack, and smoke it in plain sight, day or night, in Rio de Janeiro, Brazil. Andrea says she is married and has a home, but she keeps returning to crackland to feed her addiction. (Photo by Felipe Dana/AP Photo)

In this April 7, 2015 photo, a tourist peers through the door of a jail cell inside the now empty Garcia Moreno prison during a guided tour for the public in Quito, Ecuador. According to tour guides, this cell was nicknamed “Los Polillas”, or “The Moths”. Here, in a room designed to hold two prisoners, about 15 inmates with drug addictions were locked in overnight by the prison gangs that controlled daily life. The locked-in prisoners were also known to prostitute themselves to get access to drugs. (Photo by Dolores Ochoa/AP Photo)

A pistol is lies near the body of a drug suspect who was killed with two others in an alleged “buy-bust” operation before dawn on Friday, September 30, 2016, in Caloocan city, north of Manila, Philippines, in the continuing “War on Drugs” campaign of President Rodrigo Duterte. Duterte said he would be “happy to slaughter” 3 million addicts. (Photo by Bullit Marquez/AP Photo)

Trick rider Kendel Sampson performs during the trick riding session of the RAM Rodeo in Warkworth, Ontario, on August 1, 2013. The teenage Encore Presentation Trick Riders perform daring stunts every rodeo season in towns throughout Canada. (Photo by Norm Betts/Barcroft Media)