I find all of these stories fascinating. I've had a morbid fascination of the Cold War since I studied it in GCSE History, around the same time I watched Channel 4's brilliant 1983: Brink of Apocolypse documentary. I remember thinking when I was younger there was lasting peace since WW2 and 9/11 so the Cold War really interested me.
I gained a fascination of anything secret- secret tunnels, secret bunkers etc, and have read a lot on the subject. London's Secret Tubes is a great book. Extremely dull in a few places but otherwise a book to keep going back too.
Aside from my (sad) interest in the air raid siren network, there are all sorts of crazy things to read about. Such as the Jubille line and the awkward nuclear bunker problem, sinister truths about the Telecom Tower, BACKBONE, the Holborn deep-level telephone exchange, TURNSTILE, the express Northern Line's Cold War plans, secret cable tunnels under London etc, etc.