May 14, 2014 at 8:17 AM ET
Few Americans will ever forget the morning of Sept. 11, 2001.
"Three thousand people died on this very spot," former New York City Mayor Michael Bloomberg told Matt Lauer in an interview that aired Wednesday on TODAY, from the subterranean footprint where the twin towers of the World Trade Center once stood.
From the ashes of ground zero, there eventually arose a memorial and museum dedicated to honoring a world changed by the terrorist attacks of 9/11. The memorial opened to family members on the 10th anniversary of the attacks — and to the public the next day.
Bloomberg recently gave Lauer an exclusive tour of the new museum, opening May 21, which he calls a place of reflection and remembrance. It's a story told through an unprecedented collection of more than 20,000 images, 500 hours of footage and thousands of artifacts and interviews.
As chairman of the National September 11 Memorial & Museum, Bloomberg spent eight years spearheading the project, which some feared would never be built after projected costs soared.
Much of the exhibit is dedicated to the first responders who rushed into the buildings when others were rushing out, including a fire engine from Engine Company 21. "When I saw this, all I thought about was, 'What happened to the men on the truck?" Bloomberg said. "You and I, our natural inclination is to run away from danger. These are guys who would have kept going up the stairs even if direct orders were turn around and get out. Because that's what they do."
Visitors can also see the bullhorn that President George W. Bush, standing on the rubble, used to rally people following the attacks. "I think people walked away in the next few days with a sense of confidence," Bloomberg said. "And he deserves credit for that. "
Other items include a flight attendant's manual outlining emergency procedures and a clothing store that appears to be frozen in time, covered with dust from the tragedy.
"I think the reason it's here is to remind us that this was a place where people worked, people shopped, people enjoyed themselves," Bloomberg said. "And in fact, we have a responsibility to recreate a lot of that as well.
"It destroyed a neighborhood," he said. "It didn't destroy our ways of life, but it changed it. But also, I think it strengthened Americans, that nobody was going to take away our freedom."
"What do you want them to walk out the door thinking?" Lauer asked.
"We didn't give up," Bloomberg said. "We didn't get beaten. And that we still have a future.
"We can't let this happen again. But they didn't win. We came out of this stronger, more determined than ever, to make sure that our citizens are going to be able to enjoy what we think God meant them to enjoy."
Tune in to NBC on Thursday, May 15 for a special report on the National September 11 Memorial & Museum with Matt Lauer and Savannah Guthrie.