Devil's Tower rises 867 feet above the Belle Fourche River valley in northeastern Wyoming, a striking column of igneous rock that was the first designated National Monument in the United States. The tower's distinctive vertical columns — formed as molten rock cooled and fractured into hexagonal pillars — make it one of the most recognizable geological formations in the American West. Sacred to several Native American tribes, it is known as Bear Lodge among the Lakota.
The national monument surrounding the tower offers good hiking. The 1.3-mile Tower Trail loops the base and gives you the full sense of the scale of the thing. Prairie dog colonies dot the meadows below, and rock climbers work the crack systems on the tower's faces throughout the summer months. If you are driving between the Black Hills and points west, it is very much worth the detour.