Since the San Rafael Swell was created between 40 and 60 million years ago, various erosional forces have shaped the 40-by-75-mile expanse into a fascinating jumble of canyons, arches, hills, and valleys. Some have likened the topography to parts of Mars, which may explain why the Mars Desert Research Station was established in the vicinity. For us earthlings, the swell offers a fascinating place to explore through hiking, canyoneering, camping, and more.
