Paul Simon played a mournful, somber version of “The Sound of Silence” at the 9/11 Memorial Ceremony at Ground Zero on Sunday. He was originally scheduled to sing “Bridge Over Troubled Water,” but apparently switched.

The performance footage is interspersed with families of those felled in the Twin Tower attacks. As Pop Dust reminded us, Simon played "The Boxer" on the first "Saturday Night Live" that aired after the tragedy on Sept. 29, 2001.

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James Taylor and cellist Yo-Yo Ma also played at the memorial.  Taylor sang “You Can Close Your Eyes,” while Ma performed a Bach piece.