It's a stone that, if ever proven to be authentic, could rewrite the history books for the state of South Dakota. But was the stone actually an authentic piece of Black Hills history, or one of the greatest hoaxes of its time? Get our free mobile appCredit: Canva Credit: CanvaBack in 1887, when the stone was first unearthed, the entire Black Hills region was abuzz. It's all still up for debate, but if ever authenticated, South Dakota history would, indeed, look very different. You can learn more about the Thoen Stone and see it up close, at the Adams Museum, located at 54 Sherman Street in Deadwood, South Dakota.