Amazon Express expedition leader West Hansen paddles the Mantaro River, a possible source of the Amazon. Radius Images / Alamy ... tributary in the river's drainage basin? The current ...

The ridge divided the Amazon's flow [image], sending one side of the river eastward toward the Atlantic ... sediments eroded from the Andes filled in the Amazon basin between the mountains and ...

Humans have lived in the Amazon Basin — a vast river-drainage system roughly the size ... technology that uses lasers to generate a 3D image of the ground below — had come into vogue with ...