The museum is free but you do need a ticket for entry. You can try in advance of your visit for tickets on their website or stand in line the same day beginning at 12noon and try for an on-site same day ticket. Same day tickets really shorten your visit however.
No, but you have to have a timed ticket. The ticket will present a certain time you can enter the museum.
No you don't pay for the ticket but you have to a time stamp ticket to get in
You can also get a ticket if you're a service provider, like a fireman, etc., or an armed service person.
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