alt Hacker NewsI live a few miles away from an old SAGE blockhouse [1]. It's still imposing today - basically looks like a giant block of cement. It's interesting to see pictures of the inside of one of these things when it was in use.
[1] https://fortwiki.com/Richards-Gebaur_SAGE_Direction_Center_D...
there are several buildings like this in Manhattan. https://www.cromwell-intl.com/travel/usa/new-york-internet/p...
yeah, it looks less basic than a concrete block, but it is just a big box. this small skyscraper could offer a nice view, but it has no windows.
they used to be filled with telephone switching equipment for all the phone lines, but electronic switching has shrunk those space needs a lot. I think they've turned them into hosting providers for financial companies but I'm not positive.