This incredible canyon features the Popo Agie River (pronounced “puh-POE-zha”), which descends through the canyon in gentle cascades. What’s particularly unique about The Sinks is that the river disappears underground for about a quarter-mile, then reemerges further downstream.

It takes several hours for the water to reappear on the surface, though this same volume of water, traveling aboveground, would only take a few minutes. For years, geologists were stumped about how the river could take so long to travel such a short distance. While they still cannot confirm the passage, the theory is that there are a myriad of winding passages for the water to work through, drastically lengthening its travel time. Cracks, fissures, dead ends, and side traps create a world of obstacles for the water to overcome before reemerging and continuing its path down the canyon.

Take a night to camp in the park’s beautiful campground that rests right on the river and be sure to keep an eye on the cliffs nearby when it is dark. If you spotlights bobbing along the cliff’s face, it’s merely local mountaineers out for a night climb.