First, he modified the shape of the base, giving the corners beveled edges and fanning the corners progressively wider with the rise of the building. Then, more dramatically, Childs suggested sheathing the concrete base with vertical panels of prismatic glass. Capturing the sun, the glass prisms would surround Freedom Tower with flashes a light and color.
Newspaper reporters called the prisms an "elegant solution." Security officials approved the glass sheathing because they believed that it would crumble into harmless fragments if hit by an explosion.
In the summer of 2006, construction crews began clearing the bedrock and construction began in earnest. But even as the Tower rose, the design was not complete. Problems with the proposed prismatic glass sent Childs back to the drawing board.
Next: Ten Years after 9/11
- Revised Design for Freedom Tower Unveiled, New York Times