Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)
Riot police fire tear gas at demonstrators during a protest against fare hikes for city buses in Sao Paulo, Brazil, January 8, 2016. Brazilian riot police on Friday fired tear gas and stun grenades to disperse a violent protest against a rise in public transport fares in the country's largest city, Sao Paulo. (Photo by Nacho Doce/Reuters)
In this aerial photo taken on March 28, 2019 a hot air balloon flies over Putrajaya during the international hot air balloon festival in Putrajaya, Malaysia. (Photo by Mohd Rasfan/AFP Photo)
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)
“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)
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)
Protesters run away as the police fires tear gas during a nationwide strike demanding the resignation of Haitian President Jovenel Moise in Port-au-Prince, Haiti, Tuesday, February 2, 2021. (Photo by Dieu Nalio Chery/AP Photo)
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)