NEW YORK (AP) — The museum at the site of the 9/11 attacks in New York has gotten its 1 millionth visitor just under four months after opening to the public.

Museum President Joe Daniels said Tuesday the million-visitor mark wasn't expected to be reached until sometime in the fall but visitors recognize the museum is "a piece of history that they need to understand firsthand."

Daniels said feedback from visitors has made it clear that people want to know not only about the events of the day, but its aftermath. He noted exhibits like a shirt worn by a Navy SEAL in the raid on Osama bin Laden. Other items include debris from the downed towers, audio and video from that day, and images of people who died.

The National September 11 Memorial and Museum opened May 21. Visitors have come from all 50 states and more than 130 countries. The museum identified its 1-millionth visitor as Karen McDaniel, of Myrtle Beach, South Carolina.

The museum is part of the larger memorial at the World Trade Center site. The plaza opened to the public in 2011 and contains two huge reflecting pools with the names of those who died in 9/11 etched into them.