You can purchase tickets there. They are $15 for seniors.
You could also purchase tickets online for convenience, under General Admission--->Senior citizen tickets at https://ticketing.worldofcoca-cola.com/webstore/shop/viewItems.aspx?cg=GA&c=GAADMISSION
It's $15 for senior citizens, you can buy tickets at the window by the entrance
If you buy a city pass, it includes Coca Cola, The Aquarium, Zoo, CNN tour, and a few more places. Its $75.. so worth it.. just google city pass Atlanta. I'm not sure how much it is otherwise.
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