- The Distant Early Warning line of radar stations, in northern Canada, along with the Mid-Canada Line and the Pine Tree Line further south. Plus Texas Towers off the coasts, picket ships, and radar search aircraft.

- Mass production of bombers and fighters, with generations coming one after another rapidly. Fighters went from the F-86 to the F-106 in a few years. Bombers went from the B-36 (six props, four jets) to the B-47 (a fighter design scaled up to bomber size) to the B-52. Despite being an interim design, over 2,000 B-47 aircraft were built.

- Mass production of ICBMs. Thousands of them. Thousands of silos to put them in.

- Nuclear-powered submarines. Nuclear-powered aircraft carriers. ICBMs for nuclear powered submarines.

- USAF bases everywhere, from the Aleutian Islands to the Middle East.

- Nike air defense missile sites around all major US cities.

- Fallout shelters.

- Enough conventional weapons to re-fight WWII kept in service.

SAGE was a tiny part of all that. It was just command and control for US and Canada air defense. Not offense; that was separate, under the USAF Strategic Air Command.

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.