The Amazon River's U-Turn

The Amazon River is in South America. It is the largest river by discharge volume of water.

For millions of years, it flowed east to west. Then the Andes Mountains blocked its path.

The ancient current ran toward the setting sun.

Eleven to ten million years ago, waters worked through sandstone from the west. Sandstone is not known for its negotiation skills.

The blockage turned the Amazon Basin into a vast inland sea. This sea gradually became a massive freshwater lake.

The river took its present shape approximately 2.4 million years ago.

During glacial periods, the great lake rapidly drained and became a river. It now averages 215,000 cubic meters per second.

Today its recognized length is 6,400 kilometers. The Nile still disputes who is actually longer. The Nile has commitment issues regarding measurements.