Sinks Canyon State Park

"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."