The memorial is free but the museum is 24$ for adults 20$ for kids under 17 or students that is general admission , for a tour guide its more ,we chose general admission and was well worth the money.
The relecting pools are free. The museum charges.
There is a charge for the museum and the guided tour. Information is on the web site.
Well worth it
I know that the pools where the towers used to be is totally free to go look at, but not sure about the actual Museum.
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