Watch a two and a half minute web video adapted from the preamble of the Denver PBS documentary History on the Rocks. In this 3.8 MB MPEG-4 file, you'll witness an Equinox sunrise alignment with carvings in southeastern Colorado's Crack Cave and an elaborate Equinox sunset shadow play on a cave wall in the Oklahoma Panhandle.
These explorers trekked the dusty plains of southeastern Colorado and the Oklahoma Panhandle in a 1985 KRMA, Denver, television documentary examining the significant possibility that people from the Old World --- Celts, Libyans and Phoenicians --- explored the Arkansas River long before Christopher Columbus or Leif Ericson. The one hour television program looked at some fascinating grooves that have been translated using an Old World alphabet called Ogham. Epigraphers, those who interpret the marks, claim the precision of the shadow plays confirms what the translations herald.