A complex series of tireless geological forces has been hard at work on the Colorado Plateau for over 2.7 billion years. In other words, the Centennial State is an absolute paradise for rockhounds, from the Eastern Plains to the Central Rockies to the red rock canyons in the west. While the earthen oddities across the state inspire awe and admiration, they also often stretch the limits of geological understanding. 

Colorado is home to one of the only canyons on Earth with creeks flowing in opposite directions. It’s also where you’ll find a 40-foot natural arch formed by a volcanic dike. It even has a valley through which a river flows perpendicular—rather than parallel—to the valley’s borders. There are technicolor sandstone hoodoos, remote plateaus gushing saltwater, and jagged landscapes formed by one of the largest volcanic eruptions in our planet’s history. 

While the locations in this list cover a number of the state’s rocky curiosities, it is by no means exhaustive. Colorado is a land of boundless geological peculiarity, a place you truly have to see to believe.