Best for Kids
I've been to my fair share of natural history museums, and I have to admit, the Fernbank is well done. However, if you've ever been to a similar museum, you'll find this one isn't too out of the ordinary. Still, it's worth a visit if you're either very interested in the subject matter or if you are traveling with kids, who will love the interactive exhibits.
The main atrium has some great dinosaur skeletons, which is fun even for adults and the IMAX theatre offers showings of potentially great documentaries, depending on their schedule during your visit.
The museum is easily reached via public bus if you don't have your own car (and in Atlanta, public transit is a great thing!). Check schedules ahead of time, especially on Sundays.