NEW YORK (WABC) --Dignitaries, first responders and victims' families gathered at ground zero Thursday for the ceremonial dedication of the 9/11 Museum and Memorial, which serves as a somber reminder of the terror that occurred almost 13 years ago and the resilience of all New Yorkers.
Both President Barack Obama and first lady Michelle Obama attended, as well as Bill and Hillary Clinton, New Jersey Governor Chris Christie and former New York City mayors Michael Bloomberg and Rudy Giuliani.
President Obama was one of the many speakers to take to the podium, saying that the museum tells the story of 9/11 so that future generations will never forget, and that no act of terror can match the strength and character of the United States.
"Nothing can ever break us," he said.
Obama said it's a moment to reflect on the true spirit of September 11th and enshrine it forever in the nation's heart. He said that spirit encompasses love, compassion and sacrifice. He also praised the men and women who helped save lives in the attack, including those who gave their own in the effort.
Before the ceremony, the Obamas and Clintons took a tour and stood facing the Memorial Hall wall, lined with photos of the victims, as Bloomberg explained the display to them. Diana Taylor, Bloomberg's partner, was also part of the group.
Moments later, the group entered a massive, cavernous concrete space and walked along a wall lined with blue tiles and huge quote reading, "No day shall erase you from the memory of time."
The president walked ahead with Bloomberg, with the rest of the group slightly behind. They then turned and walked past a massive snarled antenna from one of the towers. The president and Bloomberg paused in front of the mangled remains of Ladder 3, chatting to themselves.
Additionally, rescuers and victims' relatives marked the opening at the World Trade Center site, where the story of the terror attacks is told on a scale as big as the twin tower columns and as intimate as the final voicemails of the victims.
The exhibits tell the tales of the nearly 3,000 people killed in the attacks and the World Trade Center bombing in 1993.
Bloomberg calls it a reminder that freedom is not free.
The museum covers 110,000 square feet and reaches seven stories down into the bedrock that supported the towers. There are 10,000 artifacts, 23,000 still images and 500 hours of video and film.
One survivor hopes people will learn from what they see.
"There was an explosion above us, which in memory doesn't sound as loud as you'd probably expect," one survivor said. "But what was much more dramatic than the sound was actually the movement of the building, because the building jarred to the south. And there were some people in my office who were knocked off their feet just by the movement of the building. And then it kind of came back to vertical."
There are the stairs that led so many survivors to safety, as well as the pictures of the missing, and the cross of unbent steel beams found at ground zero.
The ceremony kicked off a six-day period in which survivors, victims' relatives and recovery workers will be the only ones allowed to visit the museum before it opens to the public on May 21.
Former President George Bush released the following statement on the opening: "Americans who lived through September 11, 2001, will never forget the horror or the heroism we witnessed that morning. The 9/11 Memorial Museum in New York City will preserve the memory of that day for future generations. It will honor the sacrifice of those who lost their lives and the bravery of those who saved others. And it will help ensure that our Nation remembers the lessons of September 11th: that what happens abroad can affect us here at home, that evil is real, and that courage and love triumph over terror and hate. Laura and I thank all those who played a role in creating this inspiring tribute, and we send our best wishes to those gathered to dedicate it."
The plaza and museum together cost $700 million to build, subsidized with $390 million in tax-funded grants. Officials hope the $24 museum entrance fee expected to generate about $40 million a year will help cover operating costs, expected to be about $60 million a year. Fundraising will cover the rest, for now.