Octogon Moonrise, Octogon Earthworks, (Newark Ohio)

Built circa 2000 years ago, the Newark Earthworks are one of the largest series of mounds discovered. This web page by the Newark Earthworks Moonrise Working Group explains the astronomical events scheduled for 2005 when earth mounds at the site align for the northernmost moonrise on the horizon (which as part of an 18.6 year lunar cycle).