An air raid drill at Seattle College caught students William Bates, left, and Edna Mae Farrell, right, while they were eating their lunch in the school café, but they simply took shelter under the table and continued eating in Seattle, Washington, March 17, 1942. Air raid wardens said 350 students left their classrooms and assembled in shelters within one minute in first at the college. (Photo by AP Photo)

Cambridge policemen, known as “Bulldogs”, lined up for the University Bulldogs Chase, dressed in morning coats and top hats, 7th March 1936. (Photo by H. Allen/Topical Press Agency/Getty Images)

A green rosella and a wallaby, known as a Pademelon, eye off as they drink from a water bowl put out for thirsty wild animals at a back-yard in Kayena, in northern Tasmania, 01 February 2019. Australia recorded its hottest month on record in January; it was also the hottest and driest month on record for the Australian island state of Tasmania. (Photo by Barbara Walton/EPA/EFE)

Groundhog Club co-handler Al Dereume holds Punxsutawney Phil, the weather prognosticating groundhog, in front of the crowd gathered for the 133rd celebration of Groundhog Day on Gobbler's Knob in Punxsutawney, Pa. Saturday, February 2, 2019. Phil's handlers said that the groundhog has forecast an early spring. (Photo by Gene J. Puskar/AP Photo)

A homeless man wearing face masks to protect against coronavirus, waits to receive basic medial help from members of a group of volunteer doctors of the Dom Druzei (Home of Friends) NGO in Moscow, Russia, Wednesday, April 1, 2020. As Moscow goes into lockdown amid the coronavirus pandemic, thousands of homeless people have trouble receiving food, water and shelter as Russia's capital closes non-essential businesses, cafes and parks. (Photo by Pavel Golovkin/AP Photo)

Life in lockdown: Schoolteacher Marzio Toniolo, 35, takes a picture of his two-year-old daughter Bianca painting his toenails as they while away time at home in San Fiorano, one of the original “red zone” towns in northern Italy that has now been extended to the whole country, as his wife, Bianca's mum Chiara Zuddas looks out from their balcony, March 20, 2020. Toniolo has been documenting how his family has dealt with being under quarantine since it began for them in February. (Photo by Marzio Toniolo via Reuters)

Syrian dancer and choreographer Yara al-Hasbani performs a dance on the empty Trocadero square in front of the Eiffel tower in Paris on April 22, 2020, on the 37th day of a strict lockdown in France to stop the spread of COVID-19 (novel coronavirus). (Photo by Sameer Al-Doumy/AFP Photo)

A health worker wearing a protective suit is disinfected inside a portable tent outisee the Gat Andres Bonifacio Memorial Medical Center during an enhanced community quarantine to prevent the spread of the new coronavirus in Manila, Philippines, Monday April 27, 2020. (Photo by Aaron Favila/AP Photo)