Where do we start? The state of Amazonas is home to the world's largest and most famous rainforest, the Amazon. From its nearly mystical appeal, derived from the countless species (many yet undiscovered) in its depths, to its environmental significance as the greatest vestige of CO2 absorption on Earth, you can see why this is on the bucket list for adventurers the world over.
Manaus, the only contemporary city in this massive region, is a good place to get started, but we don't suggest you jump in the nearest fishing boat with just your flip flops and an imperialist spirit. As you can imagine, you'll need the help of local guides and preparation for the heat, humidity, and bugs. Oh yeah, and don't forget the yellow fever shots and malaria meds.
On a brighter note, most tours will offer jungle trekking, river boating, and accommodations in the forest, sometimes with local tribes. A couple prime areas from which to experience the full extent of this floral and faunal diversity are the Anavilhanas Archipelagos, which include hundreds of tiny islands in the Rio Negro, and the Mamiraua National Reserve, an immensely diverse wetlands/fisherman's paradise.
To be honest, you'll need to put aside at least 5 days to explore just a fraction of what the Amazon has to offer; and even then, because of the thick jungle foliage, you may never see the bulk of the wildlife you've heard so much about. Still, this is a Brazilian adventure you simply can't pass up. Check out our links for more details.