Smithsonian National Museum of American History, Washington D.C.

Description: This collection of steel from the World Trade Center includes a heavily damaged column assembly from the outside column ring at the 70th floor of the south tower, and two short column stubs.

Context: Despite gaping holes in the World Trade Center towers caused by the impact and penetration of the hijacked airplanes, the buildings survived the initial collision. Fuel from the airliners ignited major fires that engulfed many floors of the buildings. At 9:59 am (fifty-six minutes after being struck) the south tower collapsed and at 10:28 am (one hour and forty-two minutes after being struck) the north tower collapsed. Most experts believe the heat from the fires caused the floor trusses to fail, which allowed the outside columns to buckle outward, leading to the ultimate failure of both buildings. About 2,800 people were killed in the attack on the Twin Towers.