A hothouse teeming with millions of unknown plants and animals, Stone Age headhunters, gold prospectors and cocaine smugglers, the Amazon is the world's largest unexplored wilderness.
It is home to the world's biggest rodent, and its largest cockroach.Scientists are searching for the legendary "mapinguari," believed to be a species of giant sloth that survived from prehistory.
But despite international pressure to preserve it, the rain forest is under siege.
All over the Amazon basin, patches of the smooth green carpet of trees are being hacked out and burned, adding to the greenhouse effect that some scientists say is warming the Earth.
Last year, a swath of jungle twice the size of Delaware vanished. At that rate, the 2 million-square-mile wilderness will disappear in 251 years.
Experts say hundreds of species are wiped out each year even before they can be discovered. Only two-thirds of the Amazon's fish have names.
Behind the destruction are ranchers and farmers who clear the rain forest for pasture and plantations, and loggers who sell precious hardwoods and wood pulp to Japan, Europe and the United States.
Prospectors roam across borders, invading Indian land and poisoning the water with mercury used to extract gold from river beds.
Guerrillas allied with cocaine traffickers invade Brazil, defying the far-flung army patrols along the border with Colombia. Smugglers fly through the jungle, refueling and dropping cargo at dozens of secret airstrips.