Soldier boys at Fort Dix, N.J., learn something about guns during their working hours, as they show their girlfriends at a camp dance, December 13, 1940. In front row, playing with the coin amusement gun, from left: Pvt. Tom D'Amato of West Orange; Rose Sinkewicz, behind gun site, of Trenton; Julia Ivans of Trenton, and Pvt. Vernon Landers of Kearney. Back row: Pvts. William Sargent and William Corlies of Philadelphia. (Photo by AP Photo)

British theoretical physicist Stephen Hawking, Cambridge University Professor and Fellow, circa 1985. Stephen Hawking, the brightest star in the firmament of science, whose insights shaped modern cosmology and inspired global audiences in the millions, has died aged 76. (Photo by Gemma Levine/Getty Images)

South Vietnamese forces escort suspected Viet Cong officer Nguyen Van Lem (also known as Bay Lop) on a Saigon street February 1, 1968, early in the Tet Offensive. Moments later, Lem was executed by Gen. Nguyen Ngoc Loan, chief of the national police. (Photo by Eddie Adams/AP Photo)

A girl walks an Akita-inu dog dressed in a military uniform in Vladivostok, Russia on April 9, 2019. (Photo by Yuri Smityuk/TASS)

A model stumbles as she presents a creation by Swiss designer Albert Kriemler as part of his Spring/Summer 2020 women's ready-to-wear collection show for fashion house Akris during the Paris Fashion Week in Paris, France, September 29, 2019. (Photo by Gonzalo Fuentes/Reuters)

Social activists working for the rights of sеx workers celebrate with colour powder during the International Sеx Workers' Rights Day in Kolkata on March 3, 2020. (Photo by Dibyangshu Sarkar/AFP Photo)

Personal trainer Antonietta Orsini carries out an exercise class for her neighbours from her balcony while Italians cannot leave their homes due to the coronavirus disease (COVID-19) outbreak, in Rome, Italy, March 18, 2020. (Photo by Remo Casilli/Reuters)

A police officer sings as a hearse drives along a street as part of a campaign sponsored by the Colombian police and a funerary home to raise awareness during the new coronavirus pandemic in Envigado, Antioquia, Colombia, on April 1, 2020. More than 20,000 cases of COVID-19 were registered in Latin America and the Caribbean by Wednesday, according to an AFP tally using information provided by national health authorities and the World Health Organization. (Photo by Joaquin Sarmiento/AFP Photo)