In the nation's capital, President Obama joined the millions of Americans remembering the events of Sept.11.
President Obama and his White House staff observed a moment of silence on the south lawn of the White House to remember those who lost their lives in the terror attacks, including at the Pentagon.
The defense secretary laid a wreath this morning at the Pentagon marking the annual ceremony of the crash of flight 77 into the defense headquarters.
There was also a moment of silence to remember the 184 people killed there in 2001.