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)

A woman, with her face covered with colored powders, dances during the Holi Festival of Colors in Lisbon, Sunday, September 15 2013. The festival, which is mainly celebrated during the Hindu spring festival Holi in some regions of India and Nepal, has become popular among people in other communities. (Photo by Francisco Seco/AP Photo)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

Heavy artillery on parade during a review of the Moscow Garrison troops during the May Day celebrations in Red Square, passing posters of Lenin and Stalin. (Photo by N. Sitnikov/Hulton Archive/Getty Images). 1st May 1947

Public Space series, 2015. This series by Morteza Niknahad and Behnam Zakeri tends toward cinema, taking an almost cartoonish view of modern life in Iran. This work was inspired by the social life of dolphins. (Photo by Morteza Niknahad and Behnam Zakeri/The Guardian)

A military guard carries flowers through the Cementerio Santa Ifigenia where the remains of former Cuban President Fidel Castro were entombed December 4, 2016 in Santiago de Cuba, Cuba. The tomb stands to the side of a memorial to the rebel soldiers killed in an attack that Castro led on Santiago's Moncada barracks on July 26, 1953, and in front of the mausoleum of Cuban national hero Jose Marti. (Photo by Chip Somodevilla/Getty Images)

An Iranian girl wearing a costume inspired in the fictional folklore character Hajji Firuz, dances in Tehran on March 17, 2021 as Iranians prepare to celebrate Noruz, the Iranian New Year. Noruz, “new day” in Persian, is the New Year festivity celebrated in Iran as well as in Afghanistan and Kurdish regions in several countries. It begins with the spring equinox and symbolises rebirth. (Photo by Atta Kenare/AFP Photo)

A supporter of the Houthis has a poster attached to his waist of Iranian Major-General Qassem Soleimani, head of the elite Quds Force, who was killed in an air strike at Baghdad airport, during a rally to denounce the U.S. killing, in Saada, Yemen January 6, 2020. The writing on the poster reads: “God is the Greatest, Death to America, Death to Israel, Curse on the Jews, Victory to Islam”. (Photo by Naif Rahma/Reuters)