Due to the fear of nuclear war during the Cold War period last century and the distrust of the authorities, the United States has always had a culture of building private shelters.
Some ordinary families would buy land in the backyard or countryside, dig the ground,
and build underground radiation shelters using materials such as steel reinforcement, cement, and lead plates,
storing all kinds of items inside the shelter,
such as generators, fuel, radio receivers, sleeping bags, gas masks, radiation suits, medicine boxes, and a large amount of canned food enough for a family of three to last a long time.
Nowadays, some American construction companies specialize in building high-standard safety shelters,
fully equipped with water and electricity, furnished with cinemas, gyms, medical rooms, spa centers, kindergartens, broadcasting stations, and other facilities.
Many wealthy individuals would anonymously purchase such shelters for private use,
