Video narration
Imagine pressing both ends of a rug toward the middle. The fabric can't keep lying flat, so it gathers into raised ridges. Now picture tectonic plates-the great slabs of Earth's outer shell-moving toward each other, carrying rock layers with them. Where two continents collide, those layers are squeezed, like the rug under your hands. Under the surface, layer after layer is caught in the same squeeze. But the plates don't simply stack up. Their push folds the rock and thickens the crust. As the thicker crust is forced upward, folded layers rise into mountain ranges: fold mountains. The rug helps you see the buckling, but that's where the comparison ends. Rock is not cloth, and this process takes immense time. Remember: when continents push together, rock layers buckle and rise-like a rug pushed from both ends, on a planetary scale.