Tourists sit around a bonfire on the Makgadikgadi salt pan in Botswana. (Photo by Yang Mengxi/Xinhua News Agency/Barcroft Media)

A Chesterfield Borough Police telephone operator tests a gasmask with built in earpiece and microphone. The telephone service is considered one of the most important links in the coordination of ARP operations and must remain operational during air raids, 12th April 1939. (Photo by Fox Photos/Hulton Archive/Getty Images)

An Indian policeman wearing a virus themed helmet rides on a horse during an awareness rally aimed at preventing the spread of new coronavirus in Hyderabad, India, Thursday, April 2, 2020. (Photo by Mahesh Kumar A./AP Photo)

This picture taken on May 4, 2020 shows gentoo penguins chasing krill during feeding time in their enclosure at the Ocean Park theme park, which is currently closed due to the COVID-19 novel coronavirus, in Hong Kong. Save for an absence of gawping crowds, life for the penguins of Hong Kong's Ocean Park has been much the same during the coronavirus pandemic – but their carers have worked long shifts to keep the monochrome troupe healthy. (Photo by Anthony Wallace/AFP Photo)

A health worker dresses in a protective suit before starting to perform the coronavirus testing in an effort to stop the spread of the coronavirus disease (COVID-19) in the Kibera slum of Nairobi, Kenya, May 26, 2020. (Photo by Baz Ratner/Reuters)

Sellers sort persimmons for sale at a wholesale market in Hanoi, Vietnam October 3, 2016. (Photo by Reuters/Kham)

In this October 6, 1976 file photo a member of a Thai political faction strikes at the lifeless body of a hanged student outside Thammasat University in Bangkok October 6, 1976. For some Thais, the bloody events of October 6, 1976 are still a nightmare. On that day, heavily armed security forces shot up Bangkok's Thammasat University campus and killed scores of students, while right-wing vigilantes captured would-be escapees, subjecting them to ghoulish lynchings. (Photo by Neal Ulevich/AP Photo)

A member of the riot police gets ready to repel the attacks of protesters during a protest against President Sebastian Piñera during the seventh day of protests against President Sebastian Piñera on October 24, 2019 in Santiago, Chile. Although President Sebastian Piñera announced measures to improve equality, unions called for a national strike and demonstrations continue as casualties are now at least 18. Demands behind the protest include issues like health care, pension system, privatization of water, public transport, education, social mobility and corruption. (Photo by Marcelo Hernandez/Getty Images)