You watched this torrent of water carve out much of the present-day Illinois River valley, fill it, and also fill the former channel of the Mississippi River left empty with the westward advance of the Wisconsin Glacier about 24,000 years ago. This advance blocks the flow of water in the Mississippi’s channel and forces the river to move west to a new channel between Illinois and Iowa, where it flows today. Now we want to tell you something about the content and organization of this educational Web site.