Arnaq Egede walks to the potato field on her family's farm on July 31, 2013 in Qaqortoq, Greenland. The farm, the largest in Greenland, has seen an extended crop growing season due to climate change. (Photo by Joe Raedle/Getty Images)

Eleven-year-old Kelen loves to dance in the half-built rooms of the centre in Kabanga Refuge Centre, Tanzania, 2012. The rescue centres protect albino people from the vicious hunters who sell their body parts to witch doctors. Photojournalist Ana Palacios, 43, visited the centre in Tanzania three times between 2012 and 2016 to find out more about the plight of albino people. (Photo by Ana Palacios/Barcroft Images)

A worker spreads paddy crop for drying in a rice mill complex on the outskirts of Ahmedabad February 3, 2011. (Photo by Amit Dave/Reuters)

A British Museum representative poses for photographs next to Andy Warhol's “Mao”, left, and Jim Dine's “Drag: Johnson and Mao” which feature in “The American Dream: pop to the present” exhibition during a media photocall at the British Museum in London, Monday, March 6, 2017. The exhibition, which opens to the public from March 9 and runs until June 18, charts modern and contemporary print making. (Photo by Matt Dunham/AP Photo)

Visitors look at an artwork “Hierarchy of Prosperity” created by Indonesian artist Eko Nugroho during the VIP preview of the art fair “Art Basel” in Hong Kong, Tuesday, March 22, 2016. A set of gold-plated metal cubes, tapestries embroidered by unknown North Korean artisans and bales of cardboard waste are among the highlights of the Art Basel Hong Kong fair opening this week. (Photo by Kin Cheung/AP Photo)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

A male elephant named Mahadevan is tied in a truck as he is being transported for an annual temple festival in Kochi, India, March 10, 2020. (Photo by Sivaram V/Reuters)

Seven-year-old Mimi Meade winces from the sting as Dr. Richard Mulvaney inoculates her April 26, 1954 in McClean, Va., with the new Salk polio vaccine. Mrs. John Lucas, a registered nurse, holds Mimi's arm steady as she gets one of the first injections of the countrywide test. (Photo by Harvey Georges/AP Photo)