NEW YORK (WABC) -- Firefighters from around the world put themselves to the test in honor of 9/11 heroes.
Around 150 of them took part in the fifth annual New York City Memorial Stair Climb Saturday at Three World Trade Center.
They wore full gear while racing up the building's stairs.
Hanging on the walls of the staircases were pictures of the 343 first responders who died on September 11, 2001.
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Firefighters take part in Memorial Stair Climb at 3 World Trade Center