It's only a partial replica, but the pillars of Bamahenge are approximately the same scale as those at Stonehenge. They're even aligned with the summer solstice. But they're made of fiberglass, the creation of an artist at the request of a local billionaire. Even more impressive, within a short walking distance you'll find three very well detailed dinosaurs. The tyrannosaurus is especially noteworthy, as it's partially concealed at the edge of the woods.
If you go:
Open any time, with no admission charge. The parking lot by Bamahenge is very small, but you can also park on the shoulder of the road, and there is a larger lot about a quarter of a mile away near the dinosaurs. Officially, there's supposed to be a fourth dinosaur, a brontosaurus, but it seems to be extinct now.
Links:

Barber Parkway
Elberta, Alabama 36530 USA