Members of the contemporary circus company Cirk La Putyka perform in front of sculpture of Franz Kafka's head to entertain local residents in Prague, Czech Republic, 21 April 2020. The aim of the Cirk La Putyka events in the streets of Czech capital is to get live art back to people during the lockdown. According to them, when people can't go to the artists, to the theater, the actors go to the people. The Czech government has imposed a lockdown in an attempt to slow down the spread of the pandemic COVID-19 disease caused by the SARS-CoV-2 coronavirus. (Photo by Martin Divisek/EPA/EFE/Rex Features/Shutterstock)

Seven-year-old Mimi Meade winces from the sting as Dr. Richard Mulvaney inoculates her April 26, 1954 in McClean, Va., with the new Salk polio vaccine. Mrs. John Lucas, a registered nurse, holds Mimi's arm steady as she gets one of the first injections of the countrywide test. (Photo by Harvey Georges/AP Photo)

Metropolitan Transit Authority (MTA) Police Officer Keith Flood trains with his K-9 partner Doc, a German Shepherd, inside the “warehouse room” at the new MTA Police Department Canine Training Center in Stormville, New York, U.S., June 6, 2016. (Photo by Mike Segar/Reuters)

A child plays with a mock submachine gun at a model Mass Transit Railway (MTR) station to mark the National Security Education Day at Hong Kong Police College in Hong Kong, China on April 15, 2021. The “education day” was organized to promote the sweeping legislation China imposed last year, marked with school activities, games and shows, and a parade by police and other services. (Photo by Tyrone Siu/Reuters)

Kayaks, 7, poses for a picture holding toy gun in a camp where Christians displaced by Islamic State militants are living, in Irbil, Iraq, Friday, December 23, 2016. Iraq’s Christians are marking the holiday in his camp for displaced people with a sense of worry and despair, unable to return to their towns they were forced to flee two years ago by the Islamic State group’s onslaught. (Photo by Manu Brabo/AP Photo)

Evangelia Platanioti of Greece competes in the Solo Technical Routine at the Glasgow 2018 European Synchronised Swimming Championships, Glasgow, Britain, 06 August 2018. (Photo by Neil Hall/EPA/EFE)

A visitor jumps for a photograph on the world's highest and longest glass-bottomed bridge above a valley in Zhangjiajie in China's Hunan Province on August 21, 2016. The bridge, which opened to the public on a trial basis on Saturday, spans 430 meters (1,410 feet) and rises about 300 meters (984 feet) above a valley in a scenic zone, making it the world's highest and longest glass-bottomed bridge according to Chinese state media. (Photo by Fred Dufour/AFP Photo)

A Rafale fighter jet flies over France's Charles de Gaulle aircraft carrier as it makes its way in the Gulf, January 28, 2016. (Photo by Philippe Wojazer/Reuters)