The War
The couple realized that the fallout shelter was built when the cold war was going on. And that was in 1960. The step taken by the man was quite intelligent. Just a few years after the owner had built the shelter, the Cuban Missile Crisis occurred in the country. The shelter was the best place for Frank to hide when the tensions between the Soviet Union and the USA raised. He could sense that a war was going to happen and hence he took the safety measures to build the shelter.
