I knew Sosus was big, but looking at the maps, I hadn't realised just how big - thought it only tracked Russian subs coming out of port.
Didn't realise it covered the Atlantic Gap between UK and Greenland, as well as down past Spain!
The more one learns about the technology of the Cold War, the scope and scale is amazing.
The resources piled into operations like Chrome Dome.
Fractional Orbital Bombardment, SDI, IMINT and SIGINT.
And I'm sure us civilians still don't even know the half of it.