I worked in a underground safe room for two years. There had two sets of blast doors and you could only open one set at a time. The entrance to the building dad an air lock because the inside was kept undrt pressure so any leaks the air was exiting and could not bring in contamination. Wet air filters were impervious to all NBC agents and were in an automatic loop to keep them clean. Waterways supplied be deep, real deep wells. Generator with enough fuel to last two years with two backup generators. Full medical facility. Food for two years. NBC surface monitors and in case of attack a reserve antenna field would come up from underground. If the bombs started dropping I would rather be above ground with my family.
