Remembering the World Trade Center

Forrest M. Mims III


Five years ago the world was transfixed by surreal images on millions upon millions of television screens. A passenger jet had crashed into one of the towers of New York’s World Trade Center (Fig. 1).

Commentators posed before images of the burning tower and discussed whether the collision was accidental or intentional. Even as they speculated, a second plane could be seen behind them. As millions of us watched, it headed straight for the second tower and exploded in a massive fireball. There was no longer any need to speculate about what had happened to the first tower.

Today a gaping hole near the south tip of Manhattan marks where the twin towers of the World Trade Center stood and where nearly 3,000 souls perished. Some died instantly when the planes penetrated the towers and exploded. Some jumped from flaming offices. Those who survived the fires and suffocating smoke perished when the towers collapsed.

Even while heroic rescuers were trying to find survivors in the rubble, engineers and scientists were trying to make sense of the disaster. Since the attack, architects and city planners have completely reconsidered the design of high-rise buildings.

Should steel beams be sprayed with a flameproof coating? Or should they be packed in concrete?

How can stairwells be designed to guarantee escape routes for people trapped above a fire?

How can existing buildings be remodeled to provide better protection against fire?

During happier times, tourists lined up at the first floor of Tower 2 to take high speed elevators to the viewing windows and gift shop just below the top of the building (Fig. 2). The view from those windows was almost the same as from an aircraft approaching one of the nearby airports. Weather permitting, tourists could ride an escalator to the observation deck atop the building. My family will never forget our trip to the observation deck.

During business trips to New York City, I sometimes made atmospheric measurements from the observation deck atop Tower Two. I would point various instruments at the Sun to measure the ozone and the water vapor between the top of the building and the top of the atmosphere. Then I would rush down to the ground floor.

In the plaza by the towers, I would repeat the measurements made from high above. By subtracting the first set of measurements from the second, it was possible to learn the amount of haze, ozone and water vapor between top and bottom of the building.

Today those measurements are just numbers in a notebook. What I remember most are the happy tourists taking pictures of one another from atop the 100,000 tons of steel and 212,000 tons of concrete called Tower Two.

I especially remember the smiling supervisor who bent the rules on a very windy day and took my instruments and me to the locked observation desk when the sky was clear and deep blue. That was my last trip to the top of the World Trade Center. Where was she when the plane struck the tower?

To be all alone atop that enormous building was an experience never to be forgotten. What happened five years ago was an experience the world will not soon forget.