The enormous Amazon River of South America passes through the equator, from 2° N to 5° S. Amazingly, the Amazon River is comprised of about 2/5 of the whole continent of South America, which is also surrounded by the rainforest. Majority of the Amazon Rainforest is situated in Brazil, along with Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana obtaining just small portions of the rainforest. The Amazon Rainforest takes up about 3581 km² of Brazil's territory, which is approximately 42% of the whole country.
Tropical climate is predominant in Brazil, although near the southern part of the country, subtropical climate prevails. Due to the traverse of the equator, it is almost always scorching hot and humid. The amount of yearly precipitation that falls each year is about 2,500mm. It is estimated that about 1/5 of the whole Earth's river water is constituted in the Amazon River, and about 1/3 of Earth's rainforests are a part of the Amazon Rainforest. In addition, it is estimated that about 1/5 of all of Earth's oxygen production comes from the Amazon Rainforest. Without almost any environmental pollution, it serves as a paradise for animals and plants that live in it, not to mention the infestation of bugs and poisonous insects that becomes a yearlong pest for the humans. Deforestation has been a great threat and a subject of concern for environmentalists who worry that it might result in a world-wide dilemma as a result. Most of the forest lost through deforestations was redeveloped into ranches for cattle breeding.
One of the rivers that flow through Brazil is the Rio Negro (Black River). Starting from Columbia (Columbians call it the Guainia River), it traverses through a state in Amazon, Manaus, where it then flows into the Rio Solimoes to form a constituent of the Amazon River. The Rio Negro passes through the borders of Brazil, Colombia, and Venezuela, forming the lagoons of Sao Gabriel da Cachoeira, Santa Isabel, and Barcelo. Research studies show that about 240 Indian Tribes are settled in the rainforests of Brazil, and out of these 240 Tribes, 50 of them are still hermetic, which means they are withdrawn from the outside world and only adhere to their own traditions and cultures.
The Rio Negro River-Valley is teeming with gold, silver, and other valuable mineral stones. However, its soil is sterile due to its high acidic level. Because of the poor pedospheric condition and acidity of the Rio Negro, nutrition sustenance is very limited causing malnutrition and many other diseases for the Indian community. These environmental conditions of the Rio Negro River-Valleys were one of the reasons why national Brazilians did not colonize the area, helping to conserve about 22 Indian Tribes from colonization. One of the main cities of Brazil is Sao Paulo, which is approximately 4,500km away, a 4 hour ride through commercial airline from the Amazonas state, Manaus. About 1/5 the distance from Manaus to Sao Gabriel da Cachoeira is approximately 900km, about a 2 hour 30 minute flight on a small commercial plane.