I have a selection of 10 books for you. They are a mixture of books linked to rainforest, the amazon, Aztec gold and just interesting looking adventure stories.
Their titles are:
Journey to the River Sea by Eva Ibbotson
Running Wild by Michael Morpurgo
Rainforest Rescue by Jan Burchett
Tua and the Elephant by R.P. Harris
Hatchet by Gary Poulson
The Golden Scarab by S.W. Lothian
Secret City by Jan-Andrew Henderson
The Quest for Aztec Gold: Mexico by Elizabeth Singer Hunt
Sea Bean by Sarah holding
Maddy West and the Tongue Taker by Brian Falkner