The National 9/11 Flag is un furled during a ceremony marking the opening of the National September 11 Memorial Museum. After the ceremony, the flag was transferred into the museum's permanent collection. (Don Emmert/AFP/Getty Images)

Brittany Dutter did everything she could to visit the National September 11 Memorial Museum with her young children on Wednesday before flying home to California.

It was the first day the museum was open to the public — people had been lining up since about 8 a.m. — and she thought it important to be there.

Inside, Dutter and her children, ages 2 and 4, looked at an exhibit showing satellite footage of New York City. “This is from a spaceship, and they were able to get pictures looking down,” she explained to the them. A recording of astronaut Frank Culbertson, then a commander on the international space station, played on a loop. “I know it’s very difficult for everyone in America right now,” he says. “And for New Yorkers, your city still looks great from up here.”

Dutter and her children turned the next corner in the exhibition hall and stopped near the remains of an emergency vehicle. She bent down and quietly spoke to them.

Following the museum’s dedication last week, which featured remarks by President Obama, the exhibits had been open only to survivors and the families of those killed. On Wednesday, an honor guard of firefighters and police officers, from New York City and departments across the country, unfurled the National 9/11 Flag on the memorial lawn. And with that, the first public tours began.

Museum officials say they are taking seriously the task of explaining the events of Sept. 11, 2001, even to those who were not alive at the time.

Youngsters were an important part of the opening ceremony. Children involved with the 9/12 Project filled in among the officers, holding on to the edge of the flag.

“Kids, kids, today is a very important day. We’re here to remember, pay tribute and learn about what happened on 9/11. But we’re also here to remember, pay tribute, and to learn about what happened on 9/12,” said Jeff Parness, founder and chairman of the New York Says Thank You Foundation. “People from all around the world came here to help us in our time of need.”

Under the foundation’s supervision, the National 9/11 Flag — the tattered flag that was flown near ground zero for several weeks after the attacks — traveled to all 50 states, and over 30,000 survivors of tragedies had a hand in helping to mend it. The last repairs to the flag were made on the 10th anniversary of 9/11 in Joplin, Mo., which had been hit by a devastating tornado a few months before.

“In New York during those first days and weeks, and even those first couple of months after 9/11, there was a sense that we were all in it together,” said Alice Greenwald, director of the museum. “There’s an aspiration for this museum. It’s that we remember what that was like.”

And the museum wants to make sure that message comes through for children.

In addition to a downloadable app and a handheld audio guide, the museum offers a paper guide to visitors with children between 8 and 11, containing suggested answers to questions children might have, including “What is 9/11?,” “What were the Twin Towers?” and “Why did the terrorists do this?”

Greenwald said visiting much of the museum is like exploring “an archaeological excavation.” It includes student art from across the country and a quilt embroidered with the faces of all those who died on 9/11 and in the first World Trade Center bombing in 1993. There’s a wall covered with 2,983 squares, each a different shade of blue, representing the color of the sky on that morning.

The exhibition located in the footprint of the North Tower — titled simply “September 11, 2001” — is the only section of the museum that Greenwald warns might not be appropriate for children under 11. The museum, she said, consulted with cognitive developmental researchers who advised that young children are not able to put that traumatic history in context.

This section is replete with objects found at the crash sites and contains a minute-by-minute timeline of 9/11, in addition to graphic video footage, photographs and audio recordings. Pictures of the hijackers are a footnote on a wall between the timeline of their lives in the United States and the timeline of their activities on the morning of 9/11.

As educational programming kicks off and visitors contribute their own memories, the museum will evolve.

“It’s harder at the 9/11 museum, because the political narrative and the emotional narrative are still being negotiated,” said Sonnet Takahisa, who worked briefly as the museum’s director of education.

In a storefront around the corner from the newly opened museum is the 9/11 Tribute Center, which opened in 2006. All 600 of the Tribute Center’s docents are survivors, victims’ family members, first responders, volunteers who helped in the aftermath or people who lived in the area. On each tour, volunteer docents tell their personal stories, which, over the years, have deeply affected visitors and volunteers alike, said Wendy Aibel-Weiss, director of education and exhibits at the Tribute Center.

“It’s not just about the horror,” she said. “It’s about how you make something significant about your life.”

Downstairs visitors at the Tribute Center can gather and write notes or memories and pin them to a bulletin board. One unsigned card reads, “My brain can’t comprehend all of this memorial, and I’m too young to remember the day, but I still felt and feel my heart grow heavy and my eyes tear up.”

Hiatt is a freelance writer.