Since the end of the last ice age, Minneopa Creek has carved a ravine through sandstone bedrock, creating a spectacular double waterfall. Sometimes roaring, sometimes just a trickle, these falls have been an attraction for hundreds of years. This popular place received public protection as a state park in 1905. From the vantage point of Seppman Mill, a wind-driven grist mill built in 1864, a rocky terrace can be seen perched above the Minnesota River. This terrace was exposed by the glacial meltwaters of the ancient River Warren. Today, the hard layers of this water-sculpted bedrock terrace are covered with a thin veneer of prairie plants and bur oak trees.