Alter do Chao is probably one of the most alternative and hippie meeting point of the Brazilian Amazon. Surrounded by eco-communities, its clear water, free from crocodils (Jakarè) and piranhas allow you to swim. Just be careful to the electric race and to that little fish who enter your penis if you pee in the water!
Travelling by boat from Belem to Santander you pass by very poor local communities. The passengers use to prepare some packs of food, medicine and money to throw them at their passage.