This vicino guy bout up a bunch of munition bunkers, called igloos from the black hills ordnance depot. Its an old army base built in the 40s
Most are 13’ high,27’ across by 60-80 feet long.
Stuck in the corner of southwest south dakota.
Their brochure says they will with stand 500000 pound blast of tnt.
I worked in them in the 70s.
I wasctold then that they could take a direct hit from a two thousand pound homb.
There are over 800 of them out there but some have been converted to house pigs.
Its totally a barren out of the way place.
IMO best to be in a place nobody knows about, nobody cares about and nobody can hear or see you if the pass by. An abandoned mine with water supply would be good imo. One could drive an RV or 2 in there and some truckloads of supplies then collapse the entrance behind them. Air shafts could be excavated for an eventual exit.
These bunkers would make a great movie plot. The politics as they run out of supplies would be very interesting. One-by-one the Havenots would group up and attack someone who still has supplies. Like Ghengis Khan the offer would be join us or die. By the time the Haves figure out what is going on the Havenots would have enough members and supplies to beseige all the remaining Haves, selecting the weakest first.