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 Gnawa traditional group performs in the city of Essaouira on December 14, 2019, to celebrate the decision of adding the Gnawa culture to UNESCO's list of Intangible Cultural Heritage of Humanity. Gnawa culture, a centuries-old Moroccan practice rooted in music, African rituals and Sufi traditions, was added to UNESCO's list of Intangible Cultural Heritage of Humanity earlier in the week. Gnawa refers to a “set of musical productions, fraternal practices and therapeutic rituals where the secular mixes with the sacred”, according to the nomination submitted by Morocco. Often dressed in colourful outfits, Gnawa musicians play the guenbri, a type of lute with three strings, accompanied by steel castanets called krakebs. (Photo by Fadel Senna/AFP Photo)

A mother reacts as she pleads with police to allow her daughter to pass a checkpoint for cancer treatment after she arrived from Hubei province at the Jiujiang Yangtze River Bridge in Jiujiang, China, February 1, 2020. (Photo by Thomas Peter/Reuters)

A fisherman waits to catch fish as he sits atop a stilt in the sea in Koggala, Sri Lanka on July 4, 2019. (Photo by Dinuka Liyanawatte/Reuters)

A man wears a busho mask and a costume made of sheep pelt while climbing up a ladder outside a barn in Mohacs, Hungary, 20 February 2020, on the first day of carnival. The traditional Busho carnival, which marks the end of winter, dates back to the 16th century. According to local legend, members of an ethnic South Slavic group living in Mohacs at the time dressed up in similar costumes and wore wooden masks to scare away Ottoman invaders, who mistook them for demons. (Photo by Tamas Soki/EPA/EFE)

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 woman wears a scuba mask and a surgical mask as a precaution against the spread of the new coronavirus, while buying food in a popular market in Lima, Peru, Monday, March 23, 2020. The vast majority of people recover from the COVID-19 disease. (Photo by Rodrigo Abd/AP Photo)

A train attendant wearing a protective face mask stands on a train to Wuhan, at the railway station in Beijing, China, 29 March 2020. Wuhan, the epicenter of the coronavirus outbreak, partly lifted the lockdown allowing people to enter the city after more than two months. Chinese authorities eased the quarantine measures as cases of Covid-19 across China have plummeted, according to Chinese government figures. (Photo by Roman Pilipey/EPA/EFE)