The best thing you can do is make friends with your neighbors. Surviving disasters is a team activity.

Unless you think the bombs are going to fall, you'd be better off getting some sort of cabin than a bunker. Living underground has a lot of challenges; it's expensive to build down there and you'll constantly be fighting moisture and mold.

I think the threat model is packs of desperate people looking to take your stuff, not bombs.

Being underground won't help much if your assailants decide to smoke you out. To stop that you'd need to shoot back or have a very robust and well designed fortification, with air filtration and redundant hidden vents. If you were committed to fighting back, an above ground fortification made out of reinforced concrete would be easier/cheaper to construct and would probably give you a better view of your surroundings. You'll also need several people you trust living there with you, so you could keep lookouts stationed around the clock and cover for each other.

All in all, it seems like a hopeless scenario. A better approach is probably to make friends with your neighbors and try not to look like you have anything worth stealing.

> If you were committed to fighting back, an above ground fortification made out of reinforced concrete would be easier/cheaper to construct and would probably give you a better view of your surroundings. You'll also need several people you trust living there with you, so you could keep lookouts stationed around the clock and cover for each other.

A castle. You're describing a castle. :)

Invest in bunker REITs in Eastern Poland![1] Either way bunkers tend to be blown up by one side or another...

[1] - https://en.wikipedia.org/wiki/Wolf%27s_Lair

> try not to look like you have anything worth stealing

I think you said it all :)

If you're only building a small "bunker", it's not that expensive to build down there. Just a backhoe, a few hours, 6 sides of concrete and a tin roof.

I bet you can build your own luxury bunker somewhere in midwest for way less than a dinky studio condo would cost ya in SF. The real issue is the cost of land and zoning laws, not the actual entity built on that land (obvious exceptions apply, e.g., we are talking about buildings that fit a few families tops, obviously not something like a highrise with over a hundred of units).