Hoping to save 1 billion trees in NW Brazil:

guardian:

Photograph: Sebastião Salgado/Amazonas/nbpictures

Award-winning photographers Sebastião Salgado and Per-Anders Pettersson are taking part in Amazon, an exhibition in aid of Sky Rainforest Rescue -  a partnership between WWF and Sky that aims to help save 1 billion trees in the state of Acre, in north-west Brazil. Here is a selection of images from the free exhibition, that runs until 4 December at Somerset House, London