Speaking of the Civil War, go to the Cyclorama in Buckhead on Paces Ferry Road. A huge painting made in a circle, it is 200 feet wide and 50 feet high, so that you walk around in the middle of the painting, just fantastic.
In the same building, you can see the locomotive Texas from The Great Locomotive Chase. You can climb right up into the wheel house. Fantastic.

[Linked Image from i.imgur.com]