Devils Tower: 50 million years of erosion

Rising abruptly out of the Wyoming plains, Devils Tower is a geological masterpiece of "columnar jointing." About 50 million years ago, molten magma pushed up into the earth's crust but never reached the surface. As it cooled underground, it contracted and cracked into these near-perfect hexagonal columns—the largest of their kind in the world.

Over millions of years, the softer sedimentary rock around it washed away, leaving this massive "igneous intrusion" standing 1,267 feet above the river valley. While it looks like a single solid rock from a distance, it’s actually composed of hundreds of individual stone pillars, some up to 600 feet tall.

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