Paul Simon's Heartbreaking 'Sound of Silence' at Ground Zero

09/11/2011 at 12:55 PM EDT

"Hello darkness, my old friend …"

A somber Paul Simon performed an emotionally wrenching version of "Sound of Silence" at Ground Zero during Sunday's ceremony marking the 10th anniversary of the Sept. 11 attack on the World Trade Center.

Tears flowed among the crowd of victims' relatives and dignitaries gathered on the Twin Towers site as Simon sang the Simon & Garfunkel hit to the accompaniment of his acoustic guitar.

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