Thanks to a donation, the 9/11 Memorial Museum will be free to the public on its opening day.
Media company Condé Nast says it will pay for all tickets on May 21, when the museum accepts its first visitors.
After that, it will cost $24.
No admission will be charged for family members of victims, recovery workers and children ages five and younger.
It will also be free for everyone on Tuesdays between 5 p.m. and 8 p.m.
Tickets are on sale now.
For more information or to purchase tickets, visit 911memorial.org.