Wonder Wednesday

Did you know that the centre of the CN Tower is hollow?  In the middle of it’s three splaying legs is a hexagonal core; the same one that we can see continuing straight up above the first/lower observation pod to the base of the second/upper pod.  Which means is that this is an open shaft that runs from the ground to the base of said pod, roughly some 335m (1100′) high.  And it. Is. Most. Spectacular.  Looking so much like some giant science fiction construct, like a huge accelerator or the central spine of a space installation.  It’s awesome, in both senses of the word.

Unfortunately… that’s not entirely true anymore.  In 1997 the original location for the egress stairs (yep, the CN Tower has a set of fire escape stairs) was taken over to install an additional pair of elevators, and the stairs were moved from their outer perch to within the core.  I don’t think they take up the whole thing, but the amazing hexagonal vista is now a truncated one.

(Want to hear another amazing thing about this core and the tower as a whole?  This entire concrete structure was done using a moving slipform that slowly moved upwards about 6m per day, supported by the very structure it was building. Segments were removed from the slipform as it rose to create the tower’s iconic shape, including the final hexagonal shape that rises all the way to the base of the upper observation pod.  Amazingly it only took 4 months for it to reach that final height, and it was done so accurately that the whole thing is only 29mm off from being perfectly vertical.)

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