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)

Two men using an electric power saw to fell a tree circa 1940's. (Photo by Keystone View/FPG/Getty Images)

Reflected in the rearview mirror, Jose Collantes gets a hug from daughter Kehity while they're stopped at a red light, as Jose drives his five-year-old home from a playdate in Santiago, Chile, Sunday, September 6, 2020, three months after they lost his wife, her mother, to COVID-19. Their case highlights how COVID-19 deaths the world over are often the beginning of a new personal journey for those affected. (Photo by Esteban Felix/AP Photo)

(L-R) Ryan Regez of Switzerland, Tyler Wallasch of USA, Sandro Siebenhofer of Austria and Ferdinand Dorsch of Germany during the men's quarterfinal heat 4 during the men's Ski Cross final at the FIS Freestyle Ski World Cup event in Idre, Sweden 23 January 2021. (Photo by Pontus Lundahl/EPA/EFE)

The rusty emblem of the Soviet Union is seen over the ghost town of Pripyat close to the Chernobyl nuclear plant, Ukraine, Thursday, April 15, 2021. The vast and empty Chernobyl Exclusion Zone around the site of the world’s worst nuclear accident is a baleful monument to human mistakes. Yet 35 years after a power plant reactor exploded, Ukrainians also look to it for inspiration, solace and income. (Photo by Efrem Lukatsky/AP Photo)

Sugar gliders, Candy and Popcorn, enjoy their favourite food, Nectar, at Wild Life Sydney Zoo on February 14, 2017 in Sydney, Australia. The treat made up of honey, high protein baby cereal and egg yolks is the human equivalent to chocolate to the Sugar Gliders. St. Valentine's Day or the Feast of Saint Valentine began as a celebration of the early Christian Saint Valentinus. From the 18th Century onwards it has steadily transformed into a celebration of romantic love and sentiment in many countries around the world. (Photo by James D. Morgan/Getty Images)

In this photo taken Wednesday, March 8, 2017, a woman herder sits with her goats in a remote desert area near Bandar Beyla in Somalia's semiautonomous northeastern state of Puntland. Somalia has declared the drought a national disaster, part of what the United Nations calls the largest humanitarian crisis since the world body was founded in 1945, and with animals being central to many the drought threatens their main sources of nutrition and survival. (Photo by Ben Curtis/AP Photo)

A displaced Yemeni woman from Hodeida fills water containers at a make-shift camp in a village in the northern district of Abs in the country's Hajjah province, on May 9, 2019. The Yemeni conflict has triggered what the United Nations describes as the world's worst humanitarian crisis, with 3.3 million people still displaced and 24.1 million in need of aid. (Photo by Essa Ahmed/AFP Photo)