British photographer Jimmy Nelson has travelled the world to document the lives of millions of people in 35 of the last remaining indigenous tribes. The results are astonishing images of cultures that have been almost forgotten, among them the Maasai in Tanzania and the Kazakh, a semi-nomadic people who roam the snowy mountains and colossal valleys of western Mongolia.

Nelson’s photographs of the tribes can be seen at London’s Atlas Gallery this autumn, with the exhibition of his work running from 25 September until 16 November.