Law enforcement officers clash with protesters, Wednesday, July 20, 2016, in Cleveland, during the third day of the Republican convention. (Photo by John Minchillo/AP Photo)

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)

A police officer fires tear gas at protesters after the presidential election results were announced in Kisumu, Kenya on August 15, 2022. (Photo by Baz Ratner/Reuters)

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)

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 man smiles as he carries firewood he bought on a street amid ongoing fuel and cooking gas shortages in Yemen's capital Sanaa December 2, 2015. (Photo by Khaled Abdullah/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)