More on the Forts of Louisiana.
The Google Earth Post and the Google Earth Map (API).
Zoomed out:

A closer look:

The other thing I learned doing this is all the coastal erosion that's happened over the past 300 years or so. There are some areas that don't exist anymore.
Look at Tower Dupre (which was originally built on dry land):

Small image I used to mark forts. You might have to download it and load it into Google Earth. I'd love to get together a tour of these locations to see how some of them survived Katrina.