Man Mound National Historic Landmark: Greenfield, Wisconsin

Over a thousand years ago, people shoved and shaped the dirt here to form a sprawling 214-foot earthwork in the form of a striding person crowned with horns. It's the last surviving anthropomorphic effigy mound in North America; only five were ever known to exist, all in Wisconsin. A road was laid right across its legs in the early 1900s (appalling), but the whole area is protected now, and the feet are being restored. It's an uncanny thing to walk around, esp. when I finally found a vantage point that allowed all the seemingly random undulations resolve into order.

The old winter quarters of the Ringling Circus are just down the road in Baraboo; also worth a stop.