Unless you're eating, check out this "Keeping America Safe" video at the White House website.
While exploiting showing various photographs of 9/11 devastation, President Bush says that September 11 was, "the most significant attack in our nation's history."
Not to diminish the tragedy of 9/11, but it absolutely wasn't the most significant. One of the most perhaps.
I'm not sure where Pearl Harbor ranks on his list. It only ushered the United States into a world war in which 418,500 Americans were killed. There was another attack in 1814 in which the British army invaded Washington, DC and burned the White House and Capitol building. That was pretty significant. In 1861, shortly after the dissolving of the Union, the southern Confederacy attacked a base in Charleston Harbor called Fort Sumter. 600,000 Americans were killed in the war that followed that one. Significant.