My Grandpa built a shelter on his property with hidden air intake, toilet, pantry; large enough for our combined families to stay for the projected “2 weeks” of nuclear fallout after a blast. Plus shotgun to keep intruders out.
By the mid-60’s it had become just a large underground pantry.
Considering he was ~60 miles from an air force base in California, I think it was a very good thing to have.
I find it amazing how handy that generation was - they could build anything by hand back then it seems.