WASHINGTON — Monday marks the anniversary of the terrorist attacks on Sept. 11, 2001, that killed 2,977 people in New York, the Pentagon and in a field in rural Pennsylvania. The attacks and the reaction to them have shaped U.S. policy for more than 15 years, leaving a nation that is far more vigilant and jittery about terrorism. Yet for all of the talk about 9/11, many elements of the attacks and the actions leading up to them have receded from the public memory. Here are 10 things you may have forgotten about 9/11:
1. We don't know how the hijackers got into the cockpits of some of the planes
The comprehensive report of the commission created to investigate the attacks, which was published in 2004, said no one could determine how the hijackers were able to get into the cockpits of the four commercial airliners they hijacked.