Deep Underground Military Base

This is my new favourite conspiracy theory. Was very entertained on my morning commute!

You should know that there was a patent filed in the late 60s for a tunnel-boring-machine which used a nuclear reactor as its power source, but also used the heat-output of the reactor to melt the earth surrounding the tunnel it was boring so as to make a structurally sound tunnel

https://patents.google.com/patent/US3693731

https://patents.google.com/patent/US3885832

I’ll take a stab at it: Defensive Underground Missile Bunker Sites, or something to that effect.

I'm always concerned when people use an acronym as if everyone knows what it means, when it is in fact a fairly niche acronym. It shows people maybe haven't talked about their ideas to folks outside of a certain group with preexisting notions.