President Barack Obama says no act of terror can match the strength and character of the United States. He says, quote, "Nothing can ever break us."
Obama spoke at the dedication in New York for the National September 11 Memorial Museum. He said the museum tells the story of 9/11 so that future generations will never forget.
Obama said it's a moment to reflect on the true spirit of 9/11 and enshrine it forever in the nation's heart. He said that spirit encompasses love, compassion and sacrifice.
Obama praised the men and women who helped save lives in the attack, including those who gave their lives in the effort.
He said the deceased live on in us and in their friends and families.
The museum will be open initially to victims' families, survivors and first responders, then it will open to the public May 21.
It honors the nearly 3,000 people killed in New York, Washington and the Pennsylvania countryside.
The museum extends 70 feet underground to the twin towers' foundations.
There are scenes of horror, including videos of the skyscrapers collapsing and people falling from them.
But there also are symbols of heroism. They range from damaged fire trucks to the wristwatch of one of the airline passengers who confronted the hijackers.