Do you remember Bomb Shelters?
Some people were so afraid that "someone" was going to attack us with a nuclear bomb. Some people were so afraid that they built underground bomb shelters in their backyards.
The were usually built with thick concrete but the one advertised below was made with plywood. I would have worried that maybe the plywood would collapse from the weight of the dirt or that if we were bombed, the radiation would leak through the porous wood.
There was usually just enough room for a family of four. There were cots or bunks for sleeping, camping stoves for cooking and stored canned or boxed foods.
It still amazes me today that when we were in school, they would tell us "duck and cover" under our desks and that this would "protect" us from the radiation. Obviously they had no idea what radiation could do. Here in California, we now "duck and cover" when we have earthquakes.