11 years later: Remembering 9/11 at the White House

President Barack Obama, First Lady Michelle Obama and members of the White House staff pause during a moment of silence to mark the 11th anniversary of 9/11 on Sept. 11, 2012, on the South Lawn of the White House in Washington.

President Barack Obama, First Lady Michelle Obama and members of the White House staff pause during a moment of silence to mark the 11th anniversary of 9/11 on Sept. 11, 2012, on the South Lawn of the White House in Washington.

President Barack Obama and First Lady Michelle Obama hold hands as they walk back to the White House in Washington, Sept. 11, 2012, after joining members of the White House staff during a moment of silence to mark the 11th anniversary of Sept. 11th.

President Barack Obama, First Lady Michelle Obama and members of the White House staff pause during a moment of silence to mark the 11th anniversary of 9/11 on Sept. 11, 2012, on the South Lawn of the White House in Washington.

President Barack Obama and First Lady Michelle Obama walk out of the White House to join members of the White House staff before a moment of silence to mark the 11th anniversary of Sept. 11, on the South Lawn of the White House in Washington.

President Barack Obama, First Lady Michelle Obama and members of the White House staff pause during a moment of silence to mark the 11th anniversary of 9/11 on Sept. 11, 2012, on the South Lawn of the White House in Washington.

President Barack Obama and First Lady Michelle Obama walk out of the White House in Washington, Sept. 11, 2012, to join members of the White House staff for a moment of silence to mark the 11th anniversary of Sept. 11th, on the South Lawn of the White House in Washington.