10 years later: Remembering 9/11 with music

Singer Patti LaBelle and the Marine Chamber Orchestra perform at the "Concert for Hope" at the Kennedy Center, Sept. 11, 2011, in a performance to mark the 10th anniversary of the Sept. 11 terrorist attacks.

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Country singer Alan Jackson performs "Where Were Your Before The World Stopped Turning" at the Kennedy Center, Sept. 11, 2011, in a performance to mark the 10th anniversary of the Sept. 11 terrorist attacks.

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From left, Jill Biden, Vice President Joseph Biden, first lady Michelle Obama, and President Barack Obama arrive at 'A Concert For Hope," hosted by Washington National Cathedral, to mark the 10th anniversary of the 9/11 terrorist attacks Sept. 11, 2011, at the Kennedy Center in Washington, D.C.

Complete coverage: 9/11 anniversary

Mezzo-soprano Denyce Graves perform at the "Concert for Hope" at the Kennedy Center, Sept. 11, 2011, in a performance to mark the 10th anniversary of the Sept. 11 terrorist attacks.

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First lady Michelle Obama, left, and President Barack Obama applaud during perform at the "Concert for Hope" at the Kennedy Center, Sept. 11, 2011, in a performance to mark the 10th anniversary of the Sept. 11 terrorist attacks.

Complete coverage: 9/11 anniversary

Prsident Barack Obama speaks before the "Concert for Hope" at the Kennedy Center, Sept. 11, 2011. It was a performance to mark the 10th anniversary of the Sept. 11 terrorist attack

Complete coverage: 9/11 anniversary

Singer Patti LaBelle and the Marine Chamber Orchestra perform at the "Concert for Hope" at the Kennedy Center, Sept. 11, 2011, in a performance to mark the 10th anniversary of the Sept. 11 terrorist attacks.

Complete coverage: 9/11 anniversary

President Barack Obama speaks during the '"Concert For Hope" hosted by Washington National Cathedral, Sept. 121, 2011 at the Kennedy Center in Washington, D.C. The concert wa s to have been held in the Cathedral but was relocated aftter the house of worship was damaged in an earthhquake.

Complete coverage: 9/11 anniversary