Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

A hint of Spring Fever is evidenced by this passerby tipping his hat to a store fixture mannequin on a State St. sidewalk in downtown Chicago on March 23, 1978. The mannequin was awaiting pickup to be transported. (Photo by AP Photo)

Shoppers and commuters in Manchester wearing face masks on February 28, 2020, including plague doctor masks due to the Coronavirus crisis in the UK. (Photo by Mario Forshow/Cavendish Press)

A resident (unseen) uses a belt to get vegetables in Wuhan, in China's central Hubei province on March 13, 2020. China reported just eight cases of the coronavirus on March 13, with no new domestic infections outside the epicentre of Hubei province. (Photo by AFP Photo/China Stringer Network)

Mortuary Chamber of the Ponte San Pietro Hospital in the Province of Bergamo on March 18, 2020 – the area in Italy where the highest number of infections was recorded by COVID19 Coronavirus. (Photo by Carlo Cozzoli/IPA/SIPA Press/Rex Features/Shutterstock)

Journalists practice social distancing outside a meeting to wrap up work on coronavirus economic aid legislation to prevent the spread of coronavirus disease (COVID-19) in Washington, U.S., March 21, 2020. (Photo by Mary F. Calvert/Reuters)

Chinese women wear protective masks as they are dressed in traditional clothing from the Qing Dynasty era outside a park on March 29, 2020 in Beijing, China. A limited section of the iconic tourist site was re-opened to the public this week allowing a smaller number of visitors to reserve tickets online in advance and to enter after passing health screening. (Photo by Kevin Frayer/Getty Images)

A mural painted on a fence depicts US President Donald Trump as the Coronavirus in San Francisco, California on April, 01, 2020. All 40 million residents of California were Thursday ordered to stay at home indefinitely in a bid to battle the coronavirus pandemic in the nation's most populous state. (Photo by Josh Edelson/AFP Photo)