An outcropping (also called an outcrop) is a place where solid rock sticks up through the soil and becomes visible at the earth's surface. Imagine walking through a forest and suddenly seeing a wall of gray stone rising out of the ground, or hiking up a hillside where layers of ancient rock jut out from the grass and dirt. That's an outcropping.

Outcroppings happen because wind, rain, and ice slowly wear away the softer soil covering the rock beneath. Over thousands of years, this erosion reveals the harder stone underneath. Geologists love finding outcroppings because they can examine the rock directly without having to dig. By studying an outcropping's layers, colors, and fossils, scientists can learn what happened in that spot millions of years ago, whether it was once an ocean floor, a volcanic zone, or a desert.

Outcroppings make excellent spots for rock climbing, and many famous climbing destinations feature dramatic rock faces. They also provide natural shelter: throughout history, people have built homes and fortresses against or even inside large outcroppings.