Basically the designers had to make the glass five layers thick, using various new polymers and whatnot to ensure that the whole structure wouldn't crumble and send people plummeting to their dooms. The firm that built The Ledge and another group, who made big inroads in the glass architecture field by building all of the glass stairs that bedeck Apple stores across the nation, both have an end goal for all this alchemy: "Ultimately what we're all striving for is an all-glass structure." Sounds like fun! But, um, count us out.

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