343 people took part in the event at Madison Square Garden - including Eyewitness News Meteorologist Amy Freeze. 343 is to represent each member of the FDNY who died on 9/11.
Each person climbed the equivalent of 110 flights of stairs to represent the height of the fallen Twin Towers.
Sunday's event comes after two retired firefighters recently died from 9/11-related illnesses.
Thousands have fallen ill following their recent recovery efforts at Ground Zero
The event raised $50,000 for the families of fallen firefighters.
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