Originating on the glacier-capped peak of Nevado Mismi some 5,000 miles to the west of its mouth, the Amazon River is now said to be the longest river on Earth.  At over two million square miles, the river's basin is equally impressive, and during the South American rainy season, contributes to the enormous river's nearly third of a million cubic meters of water delivered to the Atlantic each second.
Over ten percent of the world's species inhabit the Amazon Rainforest, making it the largest collection of living plants and animals in the world.  The region houses well over two million insect species, tens of thousands of plants, and some 2,000 birds and mammal species. 3,000 fish species swim the Amazon's waters, and almost a thousand amphibians and reptiles have been classified in the region.  Twenty percent of the planet's bird species live in area rainforests.
External environmental pressure on the Amazon Rainforest has been a topic of concern ever since modern man significantly impacted it in the 20th Century, and today widespread deforestation is a global concern.  By 2000 the total forest lost in the Amazon reached over a half million square kilometers and the figure today stands at some seven hundred thousand square kilometers, or twenty percent of the total.  At the current rate, in two decades the Amazon Rainforest will be reduced by 40%.
Into this vast natural resource thousands of travelers and explorers enter annually and among them, some now carry a sensitivity to the rainforest's environmental needs.  John Maloney writes in The Guardian about such an enviromentally-sensitive travel opportunity:
After trawling the web and speaking to some of the most prominent ecogroups in Brazil, including Instituto EcoBrasil (ecobrasil.org.br) which promotes sustainable tourism, it soon became apparent that ecotourism is still in its infancy, nevertheless I earmarked four ventures to visit: Guanavenas Jungle Lodge, the first jungle lodge, set up in 1980, whose literature promises "an exquisite journey to the heart of the rainforest"; Aldeia dos Lagos, a community-run eco-establishment; Anavilhanas Jungle Lodge, one of the latest and swankiest operations; and finally Uakari Floating Lodge, three days up river from Manaus and universally regarded as the best and most ecologically sound.