Ind. circle believed to be ancient site - Science - MSNBC.com: "YORKTOWN, Ind. - A circular formation discovered in a wooded area next to a highway slated for widening is likely some sort of an earthen enclosure built by prehistoric Indians, Ball State University archaeologists say. Workers with the Delaware County Office of Geographic Information System found the earthen structure more than a year ago while studying contours on a large topographical map."
Isn't it amazing that we're still finding stuff like this? Later in the article, it mentions that you can see the feature on Google Earth, too.