Now look past the borders at the land itself. In Mountains of the World you saw the great ranges of the world. North and South America share one big pattern: tall, young mountains in the west, wide plains in the middle, and older, lower land in the east.
Key idea
The Rocky Mountains and the Andes run down the western side of the Americas. The Great Plains (North America) and the Pampas (South America) lie in the middle. The Amazon River drains the largest rainforest on Earth, and the Mississippi drains the middle of the United States.
Why it works
The Andes rise where an ocean plate slides under South America, so they are young, high and still rising, with volcanoes and earthquakes. (Earth & Space explains the plates.) The Rockies, too, are far younger and higher than the Appalachians in the east, which are very old and worn down. Rain falling on the high west drains east across the plains, which is why the longest rivers, the Amazon and the Mississippi system, flow toward the Atlantic and the Gulf of Mexico (the U.S. federal government has called it the Gulf of America since 2025).
Worked example: Highest in the Americas
Where is the highest mountain in the Americas?
- The highest peaks are in the Andes.
- Aconcagua, in Argentina near the border with Chile, is about 6,961 m (22,800 feet) high.
Answer: Aconcagua, in the Andes of Argentina.
Worked example: Which way does the Amazon flow?
The Amazon begins in the Andes of Peru, near the Pacific. Which ocean does it reach?
- The Andes block the way west.
- The river flows east across the whole continent.
- It reaches the Atlantic Ocean in Brazil.
Answer: The Atlantic.
Common mistake
Many people think the Amazon rainforest is only in Brazil. Brazil holds about 60 percent of it. The rest spreads into Peru, Colombia, Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana.