Where Rivers Begin

Every river has a source area, but for huge river systems the exact starting point can be disputed. Some rivers begin as springs where groundwater seeps to the surface. Others begin as glacier meltwater. The Amazon's headwaters lie in the Peruvian Andes: Nevado Mismi and the Apurimac system are often cited as the source of uninterrupted flow, while researchers have argued that the Mantaro headwaters are the river's most distant source. The Amazon is better treated as a network of headwaters than as one simple trickle.

The Nile's source was geography's greatest mystery for centuries. The White Nile flows from Lake Victoria. The Blue Nile begins at Lake Tana in Ethiopia. The two merge at Khartoum, Sudan, creating the river that built Egyptian civilization.