| In fact, the collapse played out just like a controlled demolition. To destroy a building, experts usually place explosives not just on the lowest three floors, but also on higher floors. With the top floors exploding, demolition experts can create what they call a "pancake effect", which you might realize is the same as a downward domino-effect. Unlike dominos, of course, the towers fell straight down rather than sideways. But their downfall was caused by the same forces that knock a line of dominos on their faces : Floors on the top gave in, crashing through the floors below them. As each concrete floor fell, it added force to the collapse - making it harder for each floor to hold up against the increasing pressure. Once the top floors gave way, the rest of the catastrophe was inevitable. |
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