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)

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)

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)

Students run past a burning barricade set up by protesters demanding the release of kidnapped people, in Port-au-Prince, Haiti, Thursday, November 25, 2021. The country is experiencing a rise in gang-related kidnappings, many demanding ransom, with the U.S. State Department issuing a warning in Aug. about the risk of kidnapping in Caribbean country. (Photo by Joseph Odelyn/AP Photo)

Riot police walk past burning garbage containers during heavy clashes with demonstrators during a 24-hour strike on March 29, 2012 in Barcelona, Spain. Spanish workers staged a general strike to protest the government's latest labour reforms, which are designed to help Spain lower its deficit within EU limits. (Photo by David Ramos/Getty Images)

“The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukrainian SSR, which was under the direct jurisdiction of the central authorities in Moscow. An explosion and fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. It is widely considered to have been the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster)”. – Wikipedia (Photos by Alexandr Strannik, August 1986; Source: LiveJournal)