A man wears a gas mask as he holds a bouquet of flowers, following the outbreak of the novel coronavirus on Valentine’s Day in Hong Kong, China on February 14, 2020. (Photo by Tyrone Siu/Reuters)

Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

Fireworks explode above St. Basil's cathedral during a rehearsal for the “Spasskaya Tower” international military music festival at Moscow's Red Square, September 4, 2015. Military bands from different countries will participate in the annual tattoo starting on Sunday. (Photo by Maxim Zmeyev/Reuters)

People assist a woman who was exposed to tear gas by pouring milk over her face after police fired tear gas and water canon to try and disperse protesters outside Parliament on November 17, 2020 in Bangkok, Thailand. The demonstrators gathered outside parliament, on Tuesday, as the Thai government met to discuss amendments to the country's constitution. (Photo by Lauren DeCicca/Getty Images)

A member of Extinction Rebellion Red Rebel Brigade protests against fracking gas outside Government Buildings in Dublin, Ireland on March 23, 2021. (Photo by Clodagh Kilcoyne/Reuters)

Riot policemen launch tears gas canisters during clashes with coca growers from Yungas in La Paz, Bolivia February 21, 2017. (Photo by David Mercado/Reuters)

“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)