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)

The New World porcupine, family Erethizontidae, 1280 Gram born at 11 April 2015 Inventory in Zoo. Counting trade Fairs Weighing the Zoo is at 7 May 2015 too the 108 Birthday Zoo Hagenbeck Hamburg, Germany. (Photo by Imago/ZUMA Wire)

Lazar and his sister Andjelka sit by a candle in their home in the eastern Serbian town of Majdanpek, December 4, 2014. Electricity workers in Serbia struggled through snow, ice and treacherous terrain on Thursday to restore electricity to an eastern town left shivering without power, heating or running water for a fourth day. (Photo by Marko Djurica/Reuters)

A man arrested for protesting over human rights abuses makes a court appearance in leg irons at the magistrates courts in Harare, Monday, September 14, 2020. Human rights defenders say it appears the government is using restrictions imposed to combat COVID-19 to suppress political criticism. Opposition officials, human rights groups and some analysts accuse Mnangagwa of abusing the rights of critics, using tactics as harsh as his predecessor, the late Robert Mugabe. (Photo by Tsvangirayi Mukwazhi/AP Photo)

A woman wears a face mask on her chin and walks past a cake depicting the coronavirus on display at the annual cake show organized as part of new year celebrations in Bengaluru, India, Tuesday, December 29, 2020. India's confirmed coronavirus cases have crossed 10 million with new infections dipping to their lowest levels in three months, as the country prepares for a massive COVID-19 vaccination in the new year. (Photo by Aijaz Rahi/AP Photo)

People walk along Beachy Head, close to Eastbourne on the south coast of England on April 12, 2020, as life in Britain continues over the Easter break, during the nationwide lockdown to combat the novel coronavirus pandemic. Britain's Prime Minister Boris Johnson was making “very good progress” on Saturday in his recovery in hospital from coronavirus, officials said, as the country's deaths toll from the disease approached the grim milestone of 10,000. (Photo by Ben Stansall/AFP Photo)

Steven Busulwa, an animal keeper, runs away from a charging rhino at the Uganda Wildlife Conservation Education Center (UWEC) amid the lockdown as part of the measures taken to prevent the spread of the coronavirus disease (COVID-19), within Wakiso district, in Entebbe, Uganda on April 20, 2020. (Photo by Abubaker Lubowa/Reuters)

Giraffes cross under the bridge of the Standard Gauge Railway (SGR) line inside the Nairobi National Park in Nairobi, Kenya, May 25, 2020. (Photo by Baz Ratner/Reuters)