The Cuban Missile Crisis (1962)

When Fidel Castro took over as leader of Cuba in 1959, having a possible communist country only 90 miles from U.S. was not comfortable for soon to be President John F. Kennedy. In April of 1961 Kennedy launched an attack that is known to this day as the bay of pigs. Unfortunately for the U.S. this attack was a flat out failure, leaving Castro to respond by being backed by Soviet forces.
    This then lead to the Cuban Missile Crisis a little over a year later. The Soviets found out about another attempt from the U.S. to oust Castro, and so they decided to take precautions of their own and built missiles in Cuba. America responded by putting their own missiles in Turkey, right outside Soviet lines. It was the closest up until this point in time that the U.S. and the Soviets were on the brink of nuclear war. It was also the closest it ever got to actually becoming a nuclear war ever. This concept of Mutually assured destruction (“where if you blow me up, I’ll blow you up”) ultimately kept the missiles on the ground and really started to get people to think, “Hey, maybe the Atom bomb is not the best idea” and start advocating for nuclear disarmament. Again, another moment in history where if something else happened, it could have ended all the other history we’ve made up until now.