Vehicle lights illuminate a street after a massive blackout, in San Juan, Puerto Rico, Thursday, September 22, 2016. Puerto Ricans faced another night of darkness Thursday as crews slowly restored electricity a day after a fire at a power plant caused the aging utility grid to fail and blacked out the entire island. (Photo by Carlos Giusti/AP Photo)

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

People participate in the first day of Thingyan Water Festival in Naypyitaw, Myanmar on April 13, 2018. The annual water festival, known as Thingyan, features large groups of people congregating to celebrate the by splashing water and throwing powder at each other's faces as a symbol of cleansing and washing away the sins from the old year. It marks the start of the traditional New Year and is similarly celebrated in countries such as Myanmar, Thailand, Laos and Cambodia. (Photo by Hein Htet/EPA/EFE/Rex Features/Shutterstock)

In this Monday, March 18, 2019 photo, a street artist performs in Caracas, Venezuela. Venezuelans are facing a severe economic and political crisis as President Nicolas Maduro has remained in power despite heavy pressure from the United States and other countries arrayed against him, managing to retain the loyalty of most of Venezuela's military leaders. (Photo by Natacha Pisarenko/AP Photo)

A lone male cheetah is set upon by a pack of African wild dogs. Peter Haygarth had been following the dogs as they hunted in Zimanga Private Game Reserve in KwaZulu-Natal, South Africa. On first encountering the cheetah, the dogs were wary, but as the rest of the pack arrived, their confidence grew and they began to encircle the cat. Peter kept his focus on the cat’s face. In a few minutes the spat was over as the cheetah fled. (Behaviour: mammals category). (Photo by Peter Haygarth)

A member of the public wears a pandemic face mask ahead of the prime minister announcing the government's Covid-19 winter strategy on September 13, 2021 in Manchester, England. Tomorrow, British Prime Minister Boris Johnson will set out his plan to manage Covid-19 through the winter, including what actions would need to be taken if the NHS hospital system were at risk of being overwhelmed. (Photo by Christopher Furlong/Getty Images)

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)

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)