The Amazon basin is bounded by the Guiana highlands in the north and the Brazilian highlands in the south. In between is the Amazonas region of Colombia as well as the amazon regions of other countries .
The river systems and flood plains in Brazil, Peru, Ecuador, Colombia and Venezuela whose waters drain into the Solimões and its tributaries are called the "Upper Amazon".
The Amazon Rainforest begins from the eastern edge of the Andes. It is the largest rainforest in the world and is of great ecological significance, as its biomass is capable of absorbing enormous amounts of carbon dioxide. Conservation of the Amazon Rainforest has been a major issue in recent years.
The rainforest is supported by the extremely wet climate of the Amazon basin. The Amazon, and its hundreds of tributaries, flow slowly across the landscape, with an extremely shallow gradient sending them towards the sea.
The biodiversity within the rainforest is extraordinary: the region is home to at least 2.5 million insect species, tens of thocolombiands of plants, and some 2,000 birds and mammals. One fifth of all the world's species of birds can be found in the Amazon rainforest.
The diversity of plant species in the Amazon basin is the highest on Earth. Some experts estimate that one square kilometre may contain over 75,000 types of trees and 150,000 species of higher plants. One square kilometre of Amazon rainforest can contain about 90,000 tons of living plants.
Much of the jungle through which the eastern Caquetá originally flowed has been cleared for pasture, crops of rice, corn, "yuca" (manioc), and sugar cane, and in the past two decades, particularly coca crops.
The Amazon River which rises in the Andes Mountains at the west of the basin, is the second largest river in the world. It covers a distance of about 6,400 km before draining into the Atlantic Ocean. The Amazon and its tributaries form the largest volume of liquid water in the world. The Amazon accounts for about 20% of the total water carried to the oceans by rivers.