Some of London's telephone operators and engineers, trying out their gas masks at the anti-gas civilian training centre in Gloucester, where they were taught how to deal with gas attacks. (Photo by Harry Todd/Fox Photos/Getty Images). 13th February 1937

U.S. soldiers wrestle with South Korean soldiers in a muddy ring during a joint ranger training exercise at a ranger camp near the demilitarised zone (DMZ) June 25 2003 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

A soldier fires a rocket gun as Ukrainian soldiers in the Donetsk region, where the country's most intense clashes occur, attend intensive combat training by using both domestic and foreign weapons amid Russia-Ukraine war in Donetsk, Ukraine on May 08, 2023. Infantry is always prepared in a conflict where heavy weaponry like aircraft, helicopters, tanks and other heavy armored vehicles, artillery systems, and mortars are widely deployed on frontline. Combat readiness and experience training of the 57th Brigade of the Ukrainian army continues in Donetsk. (Photo by Muhammed Enes Yildirim/Anadolu Agency via Getty Images)

A store mannequin with a protective mask stands before a clothes store as they open for the first time since March during the novel coronavirus (COVID-19) pandemic on April 22, 2020 in Berlin, Germany. Small to midsized-shops are opening across Germany this week as state authorities follow a recommendation by the federal government to ease restrictions imposed in March meant to slow the spread of the coronavirus. Some schools are also planning to reopen soon, as are museums and hair salons in coming weeks. (Photo by Maja Hitij/Getty Images)

Dutch cyclist Fabio Jakobsen's bicycle (behind, L) flies through the air as he collides with compatriot Dylan Groenewegen (on the ground, L) during the opening stage of the Tour of Poland race in Katowice, southern Poland on August 5, 2020. The Dutch rider was fighting for his life on Wednesday after he was thrown into and over a barrier at 80km/h in a sickening conclusion to the opening stage of the Tour of Poland. (Photo by Szymon Gruchalski/Forum/AFP Photo)

Emma Raducanu of Great Britain hits a return to Belinda Bencic of Switzerland during their quarterfinals round match on the tenth day of the US Open Tennis Championships the USTA National Tennis Center in Flushing Meadows, New York, USA, 08 September 2021. The US Open runs from 30 August through 12 September. (Photo by Justin Lane/EPA/EFE)

Students of the General Yermolov Cadet School take part in combined military training with members of a local youth military patriotic club at a boot camp of the Russkiye Vityazi (Russian Knights) military patriotic club in the village of Sengileyevskoye outside Stavropol, Russia February 8, 2017. (Photo by Eduard Korniyenko/Reuters)