I think this is a really pretty map (you can click for a bigger version).

What you're looking at is the southern tip of Illinois near Cairo (see below). The different colors represent the various courses (meanders) the Mississippi River has taken in the past. It was put together using old maps and aerial photographs by Howard Fisk in 1944 for the Army Corps of Engineers.
There are a more in the series, and they can be found on
radicalcartography.net.
View Larger Map