As man tired of the inaccuracies of the internal clock, other methods of keeping time were sought out … the first of which was the calendar. Not as we know it today but rather the movement of the stars, the moon, and the sun. Yes, that is correct “the movement of sun” … keep in mind that in these early times it was thought that the earth was stationary at the center of the universe and that all the planets and stars, including the sun, were revolving around the earth. Native Americans built cairns aligned to particular stars in the sky which would identify seasonal changes and animal migrations. The ultimate “cairn” is Stonehenge, located in Great Britain. Space does not permit a detailed description of Stonehenge but feel free to click on the following link for more details:Stonehenge@Wikipedia . To be continued …