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)

People observe a protest against a new citizenship law from a bus, in New Delhi, India, January 3, 2020. (Photo by Anushree Fadnavis/Reuters)

Andrey Karr from Western Riders Slacklines at sunset above big waves in Nazare, Portugal on December 27, 2017. (Photo by Aidan Williams/National Geographic Travel Photographer of the Year Contest)

Visitors are seen inside a newly opened bookstore in Chongqing, China on January 29, 2019. Covering an area of 1,400 square meters, the Zhongshuge Bookstore in Chongqing attracts readers with its creative decor. (Photo by Reuters/China Stringer Network)

Two animatronic velociraptors are on display during a technical rehearsal of “Walking with Dinosaurs The Live Experience” at the Indoor Stadium in Singapore, 29 August 2019. “Walking with Dinosaurs The Live Experience” is based on the BBC series of the same name and will run from 29 August to 08 September. (Photo by Wallace Woon/EPA/EFE/Rex Features/Shutterstock)

Cara Delevingne poses onstage for Savage X Fenty Show Presented By Amazon Prime Video – Show Sneak Peak at Barclays Center on September 10, 2019 in Brooklyn, New York. (Photo by Dimitrios Kambouris/Getty Images for Savage X Fenty Show Presented by Amazon Prime Video)

A recruitment drive during the First World War at Trafalgar Square, London. (Photo by Central Press/Getty Images)

Children clean the interior of a granary in preparation for grain storage in Odek village, north of Uganda capital Kampala February 14, 2015. Odek is the birthplace of Joseph Kony, founder and leader of the rebel group Lord's Resistance Army. The LRA rose up against the government in northern Uganda under the leadership of Kony in the late 1980s and has been accused of abducting children to serve as fighters and s*x slaves. (Photo by James Akena/Reuters)