Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

Migrant children run away from clashes with Mexican National Guards after their group crossed the Suchiate River on foot from Guatemala to Mexico, on the riverbank near Ciudad Hidalgo, Mexico, Monday, January 20, 2020. More than a thousand Central American migrants hoping to reach the United States marooned in Guatemala are walking en masse across a river leading to Mexico in an attempt to convince authorities there to allow them passage through the country. (Photo by Santiago Billy/AP Photo)

Monks attend a prayer service for blessing at the Gandan Temple in Lhasa, capital of southwest China's Tibet Autonomous Region, February 5, 2020. Tibetan Buddhist temples held prayer services to support novel coronavirus-infected areas in China. The monks here were also organized to donate money to help fight against the epidemic. (Photo by Chogo/Xinhua News Agency)

Schoolchildren from local schools take part in the children's races prior to the annual Pancake race in Olney, Buckinghamshire, England, Tuesday, February 25, 2020. Every year women clad in aprons and head scarves from Olney and the city of Liberal, in Kansas, USA, run their respective legs of the race with pancakes in their pans. According to legend, the Olney race started in 1445 when a harried housewife arrived at church on Shrove Tuesday still clutching her frying pan with a pancake in it. (Photo by Alastair Grant/AP Photo)

A woman wearing a face mask as a precaution against the COVID-19 while using smartphone in a subway train in Hong Kong, Thursday, February 27, 2020. As the worst-hit areas of Asia continued to struggle with a viral epidemic, with hundreds more cases reported Thursday in South Korea and China, worries about infection and containment spread across the globe. (Photo by Kin Cheung/AP Photo)

A man shelters from the rain with plastic bags, at a market in Tembisa, east of Johannesburg, South Africa, Monday, March 23, 2020. South Africa, Africa's most industralized economy and a nation of 57 million people, will to go into a nationwide lockdown for 21 days from Thursday to fight the spread of the new coronavirus. (Photo by Themba Hadebe/AP Photo)

National Police members disinfect Venezuelan citizens returning to the country from Colombia, as a preventive measure against the spread of the coronavirus –COVID19- at the Simon Boliviar International Bridge, in Cucuta, Colombia-Venezuela border, on April 4, 2020. Since the first case of COVID-19 was detected last March 6, Colombia has reported 1,406 people infected and 32 dead. (Photo by Schneyder Mendoza/AFP Photo)

A municipality worker in a protective suit feeds street cats at Sultanahmet Square, as the spread of coronavirus disease (COVID-19) continues in Istanbul, Turkey, April 9, 2020. (Photo by Umit Bektas/Reuters)