Some of London's telephone operators and engineers, trying out their gas masks at the anti-gas civilian training centre in Gloucester, where they were taught how to deal with gas attacks. (Photo by Harry Todd/Fox Photos/Getty Images). 13th February 1937

A model stands next to a BMW X6 AC Schnitzer car at Auto China 2012 in Beijing in this April 24, 2012 file photo. Amid the razzmatazz, music and crowds at the Shanghai autoshow on Monday, hundreds of attractive young women, and men, mingled among the stands and company booths, introducing the newest sedans and handing out pamphlets. For years, models have been a staple at China's big autoshows – as much of a draw as the latest car models themselves. 2015 is different – the organisers have banned models from the Shanghai show. (Photo by Jason Lee/Reuters)

Visitors wearing face masks walk near the Gwanghwamun, the main gate of the 14th-century Gyeongbok Palace, and one of South Korea's well-known landmarks, in Seoul, South Korea, Saturday, February 22, 2020. South Korea on Saturday reported a six-fold jump in viral infections in four days to 346, most of them linked to a church and a hospital in and around the fourth-largest city where schools were closed and worshipers and others told to avoid mass gatherings. (Photo by Lee Jin-man/AP Photo)

Richardson Fremond leaps over a wall as he runs to collect an award during a graduation ceremony for the senior class of Chambers High School at Homestead-Miami Speedway, Tuesday, June 23, 2020, in Homestead, Fla. Forty-one seniors graduated from the school and crossed the start-finish line to receive their diplomas, during the coronavirus pandemic. (Photo by Wilfredo Lee/AP Photo)

Yang Juan, an employee at Goopal Group, takes a nap in her seat after lunch, in Beijing, China, April 21, 2016. Office workers sleeping on the job is a common sight in China, where a surplus of cheap labour can lead to downtime at work. But in China's technology sector, where business is growing faster than many start-up firms can hire new staff, workers burn the midnight oil to meet deadlines and compete with their rivals. Some companies provide sleeping areas and beds for workers to rest during late nights. (Photo by Jason Lee/Reuters)

Ballerinas Kennedy George, 14, and Ava Holloway, 14, pose in front of a monument of Confederate general Robert E. Lee after Virginia Governor Ralph Northam ordered its removal after widespread civil unrest following the death in Minneapolis police custody of George Floyd, in Richmond, Virginia, U.S. June 5, 2020. (Photo by Julia Rendleman/Reuters)

People take part in a protest outside the Department for Education, London, Sunday August 16, 2020, in response to the A-level results. The British government has been urged to “get a grip” over how grades are being awarded to school students, who were unable to take exams earlier this summer because of the coronavirus pandemic. The latest confusion emerged late Saturday when England’s exam regulator launched a review on its own just-published guidance on how students can appeal grades awarded under a complicated system. (Photo by London News Pictures/The Sun)

A delegate poses for a photo at the end of the closing ceremony of the 20th National Congress of the Chinese Communist Party in front of the Great Hall of the People in Beijing, China, on Saturday, October 22, 2022. President Xi Jinping is officially set for a third term surrounded by allies, after key Communist Party officials without close ties to the Chinese leader exited the nation's top leadership body. (Photo by Bloomberg)