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)

A man takes a selfie next to a flooded street due to the overflowing of the Mapocho river during heavy rains in Santiago on April 17, 2016. Four million people in Santiago were without tap water Sunday after unusually heavy rain pounding central Chile triggered landslides that fouled the city's water supply and forced the closure of the world's biggest copper mine, officials said. (Photo by Martin Bernetti/AFP Photo)

The snitch runner takes the broom from between the legs of a Werewolves of London quidditch player during the Crumpet Cup quidditch tournament on Clapham Common on February 18, 2017 in London, England. (Photo by Jack Taylor/Getty Images)

Revelers of the “Societe des Champs Elysee” launch fireworks before boarding the Rampart-St. Claude street car line, which just opened last fall, to commemorate the official start of Mardi Gras season, in New Orleans, Friday, January 6, 2017. (Photo by Gerald Herbert/AP Photo)

A veterinarian from the zoo of Besancon feeds “Soa”, a female crowned sifaka, in Besancon, eastern France, on February 18, 2019. The crowned sifaka is a critically endangered species from Madagascar. There were only 6 females over 20 individuals living in 7 zoos worldwide end of 2018. (Photo by Sébastien Bozon/AFP Photo)

An Egyptian passenger sits on the locomotive of a train as it leaves Cairo train station in Egypt, Wednesday, October 14, 2015. (Photo by Amr Nabil/AP Photo)

Best portfolio winner. Roseate Spoonbill, Platalea ajaja, by Petr Bambousek, Czech Republic. (Photo by Petr Bambousek/2018 Bird Photographer of the Year)

Michelle Rodriguez attends the European Premiere of “Widows” and opening night gala of the 62nd BFI London Film Festival on October 10, 2018 in London, England. (Photo by James Gourley/Rex Features/Shutterstock)