Enthusiasts gathered at Cad East in Snowdonia National Park, England to take pictures of F-15 Eagle fighters as they completed the Mach Loop, November 2017. (Photo by Caters News Agency)

Performers Roni, Liv and Becky behind the scenes at Great Yarmouth Hippodrome Circus, England. (Photo by Nick Warner/The Guardian)

Italian rider Eva Lechner competes in the women's elite race of the “Hotondcross” cyclocross, the competition's fourth stage of the DVV Trofee Cyclocross in Ronse, on December 14, 2019. (Photo by David Stockman/BELGA/AFP Photo)

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)

These Arab recruits line up in a barracks square in the British Mandate of Palestine, on December 28, 1940, for their first drill under a British solider. Some 6,000 Palestinian Arabs signed up with the British Army during the course of World War II. (AP Photo)

A child stops by a large print at a photographic memorial for those killed in the confrontation between Ukraine's military and the pro-Russia separatist forces in Sievierodonetsk, Luhansk region, eastern Ukraine, Wednesday, February 23, 2022. Ukraine urged its citizens to leave Russia, and Europe braced for further confrontation Wednesday after tensions escalated dramatically when Russia's leader received authorization to use military force outside his country and the West responded with a raft of sanctions. (Photo by Vadim Ghirda/AP Photo)

Medical students play with coloured powder as they participate in Holi celebrations, the Hindu spring festival of colours, inside Moti Lal Nehru Medical College campus in Allahabad on March 16, 2022. (Photo by Sanjay Kanojia/AFP Photo)