Originally Posted by SFContributor
Something I've always wondered about, does anyone know how damaged the North Tower was after the South Tower collapse? I imagine that the concourse and the lobby probably took damage.
There is video taken after the collapse of 2WTC that shows the crushed Marriott Hotel, and shows some significant facade damage to the south face of 1WTC, including a portion where some perimeter columns appear to be missing. Unfortunately smoke and dust obscures most of the damage, but the damage appears to start a few floors below the first pair of mechanical floors (43-44), and trailing down from there. I've seen the video on Youtube, I'll see if I can find it and post a link to it here. There's also video of firefighters in the lobby of 1 during the collapse of 2, the video is located here
I'm sure the plaza and at least the first floor of the concourse was destroyed by the collapse of 2. If the collapse of that tower could flatten 4WTC (literally flattened), imagine what it did to the underground.