The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

A schoolgirl walks on an under-construction railway track at Navapura, on the outskirts of Ahmedabad, November 29, 2019. (Photo by Amit Dave/Reuters)

An young exhibitor chases his wayward pig during the Great Yorkshire Show on July 12, 2011 in Harrogate, England. The annual Great Yorkshire Show has attracted a record number of 12,700 livestock entries over the three day event. The show now in its 153rd year is Britain's leading agricultural gathering, where over 125,000 visitors come to celebrate the farming community and their way of life. (Photo by Christopher Furlong/Getty Images)

Claire and Rupert Callender of the Green Funeral Company pose for a photograph with a environmentally friendly coffin in woodland close to their office at Dartington Hall Estate on February 4, 2011 near Torquay, England. The Devon-based company operates as funeral directors and undertakers throughout the South West, offers an ecological alternative to traditional funerals, with coffins made from ecologically friendly materials such as wicker and bamboo, and can arrange funerals that encompass diverse religious and spiritual beliefs everything from a Catholic Requiem Mass, to a Pagan ritual at a stone circle on Bodmin Moor. (Photo by Matt Cardy/Getty Images)

A leopard leaps into a muddy waterhole to catch a fish on August 13, 2015, in the Savuti Channel in Botswana. A leopard leaps into a muddy waterhole to catch a fish in the Savuti Channel in Botswana. The spotted predator stood poised waiting for a fish to appear – before leaping in ferociously with lightening reflexes. Coated in a layer of thick dark mud the big cat emerged from the water clutching the fish in its jaws. The fishing leopards of Savuti are known for their unique skills in catching fish – but have rarely been photographed. (Photo by Greatstock/Barcroft Media)

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)