National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

Athletes from Australia's Olympic team going to the 2016 Olympics in Rio present their uniforms alongside Brazilian Samba dancer Sashya Jay at an official unveiling ceremony at Sydney's Bondi Beach, March 30, 2016. (Photo by Jason Reed/Reuters)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

Demonstrators protest the shooting death of Alton Sterling near the headquarters of the Baton Rouge Police Department in Baton Rouge, Louisiana, U.S. July 9, 2016. (Photo by Jonathan Bachman/Reuters)

A horse rolls in mud in the Romani camp in Velykyi Bereznyi urban-type settlement, Zakarpattia Region, western Ukraine on February 28, 2021. (Photo by Ukrinform/Rex Features/Shutterstock)

Festivalgoers are seen during the 2019 Coachella Valley Music And Arts Festival on April 20, 2019 in Indio, California. (Photo by Emma McIntyre/Getty Images for Coachella)

Relatives of the Afghan Army soldiers, who are trapped in Obde district of Herat while fighting against Taliban militants, protest to demand the government evacuate the injured soldiers, in Herat, Afghanistan, 17 June 2021. Afghan authorities said they are in the process to arrange the evacuation of Army soldiers from the restive district soon. There has been a particularly bloody spike in violence in the country in recent weeks, following the start of the withdrawal of US troops from the country, a process due to be complete by September 11. (Photo by Jalil Rezayee/EPA/EFE)