Chaco Canyon is a shallow, ten-mile canyon situated in northwestern New Mexico, seventy miles from the nearest town and accessible only by dirt roads. The canyon was carved from ancient sea beds by centuries of erosion; millions of years of history reveal themselves in the layers of rock and the fossils embedded in them. In addition, evidence suggests that the Chacoans were expert skywatchers with clear knowledge of the patterns of the sun, moon, and stars. Join the Exploratorium in this investigation about this fascinating ancient site.