Mountain Building

Mountains are among Earth's most breathtaking features. But how do they form? The answer lies in plate tectonics—the movement of Earth's plates reshaping the surface over millions of years.

Most mountains form near plate boundaries. The tallest mountain range, the Himalayas, began forming around 50 million years ago when the Indian plate collided with the Eurasian plate, crumpling and thickening the crust.

Mountains can also form through oceanic plate subduction. For example, when the Nazca plate subducts beneath the South American plate, it generates volcanic peaks in the Andes Mountains, including Cotopaxi, the world's second-highest active volcano.

Some mountains emerge at divergent boundaries, where plates pull apart. The continental crust can rift and break into large blocks that shift, creating alternating mountain ranges and valleys. This process, called block faulting, forms landforms like the Basin and Range Province near Death Valley, California.

Like the North Cascades in Washington, volcanic arcs develop where oceanic plates sink beneath continental plates.

Tectonic forces continuously build mountains through collision, subduction, or rifting, shaping Earth's surface.