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In order to pay tribute to those lost in the attacks on Sep. 11, 2001, over 60 runners will complete a 240-mile run from the Pentagon to Ground Zero on Tuesday. The Promise Run is a relay that tests the physical mettle of its runners, but as they say, the physical discomfort is made well worth it by the cause.

"The little bit of pain, the little bit of pressure we're going through, the tightness in our legs… it's nothing compared to what those folks faced that day," runner Mark Giuffre said on Monday, via CBS News.

The race began on Sunday with a 90-mile run that ended in Elkton, Maryland. On Monday, an 80-mile trek took runners to Trenton, N.J. Finally, on Tuesday, the final 80 miles will take the participants to Ground Zero.

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The event has raised more than $65,000 for Hope for the Warriors this year. The charity is a nonprofit that helps the military, veterans and their families post-9/11.

Joe Torillo, a retired FDNY first responder who was buried in the debris of the towers, met the runners before the final day. He said via CBS News "I want that day to be remembered. All the heroes carried to the cemetery, and just to keep the memory alive for all the victims and their families."

This is certainly one way to remember.