Tours combine the natural, historical and commercial aspects of the Amazon. The agency's private 800 hectare rainforest plot has good hiking and swimming; on the way there, you'll drive past vast soy plantations – a macabre yet arresting sight. Multiday tours continue to Fordlândia.

Big Tree is a branch of Zero Impact Brazil, an American-owned company that gathers the leftover parts of trees cut down by developers and resells them for specialty use, from pool cues to high-end guitars. Ask about visiting ZIB's sawmill in Santarém, with its incredible array of Amazonian timber, including 'tiger wood' and 'purpleheart.'