The original Woodhenge was built
as a calendar at Cahokia by the Mississipian Indians about 1000 A.D.
The original circle was 410 feet in diameter and was composed of 48 cedar
posts. Fourty posts are currently reconstructed in their original
positions. During excavations red ochre has been found, suggesting
the poles were at one time painted red. It is unknown at this time
what the functions of all of the posts were, but three are known to have
been used to mark the equinoxes and summer and winter solstices, observed
from the center post.