[Sherman Logan]

Uhh, air supply?

Below ground with enemies above is a bad idea. Just ask various Japanese or Germans in bunkers.

Seal off the vents, or pour gasoline into them and drop a match. Of course the second alternative does tend to reduce the plunder potential.

[Owl558]

“Just ask various Japanese or Germans in bunkers.”

By the time the japs and krauts conquered freaking Kansas, there’d be nothing left of the country anyway.

People need their security blankets.

[Rapscallion]

Uhh, air supply?

And even without the enemy above ground, you live in a constant cloud of RADON gas 24/7 down below.

[bgill]

Uhh, air supply? Below ground with enemies above is a bad idea.

Exactly. Then there's the real possibility that when you did get there, the other will have barred the door and you'd be stuck out. Nope, they can have it and more power to the guy for getting 7 million each.

[MasterGunner01]

These underground missile sites, silos, and communications shelters had full NBC (nuclear, biological, chemical) protection. In cases of heavy contamination, there were CO2 scrubbers (like nuclear submarines) so that the occupants could recycle their own air and be completely independent of outside contaminants.

These sites were also hardened to stop serious ground attacks. There was always at least one escape tunnel or manhole to get out if the main entry was blocked. Entrance was through heavy blast doors that were designed to resist nuclear explosions. There were containment areas (”kill zones”) built into the entry so that attackers could be stopped and neutralized.

I've always thought that such Cold War relics would be great for SHTF scenarios. Because many of the communications shelters weren't decommissioned until the 1990s, these are the sites most likely to require the least work. The shelters have about 7,800 square feet of living space, are steel re-bar reinforced concrete at least two feet thick, and located at least six feet below ground.

There are several problems: (1) how much work is required to make the site habitable and (2) the site location [how far away is it from where you are].

Unless the habitation systems (fuel, power, HVAC, lighting, sewer, water) were operational, you could spend a small fortune making the place livable.

The other problem is accessibility on a short notice. You have to be able to get to your shelter and that could be a problem if it is far away or there is a panic and breakdown of society.

Once these issues are addressed, these site are totally self-contained and very secure.