The "fat man" - the bomb dropped on Nagasaki

The Americans and Soviets both worked on developing atomic weapons during World War II. Though the Soviet Union was an ally of the United States, the program was not disclosed to Stalin. Truman did not become aware of the program until he became President. Truman told Stalin about the weapons at the Potsdam Conference in June of 1945, but Stalin already knew about them because he had spies working in the American program. Truman made the decision to drop the first atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August of 1945, ending the war with Japan.

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American backyard fallout shelter 1960

The Soviets were not far behind the US in developing the atomic bomb and accomplished it in 1949.

Once the Soviet Union successfully tested the atomic bomb, the arms race was on. Both the Soviet Union and the United States continued to seek weaponry advantages in numbers, speed and distance.

MAD (mutually assured destruction) was designed to keep both sides from "pushing the button," by giving both sides equality in "kill power."

Intercontinental Ballistic Missiles (ICBMs) were designed in the cold war to carry a long range nuclear payload and were developed by the Soviets in 1957. The ICBM made the US more vulnerable to nuclear attacks (25 minutes). Four months later the Americans were successful with their own ICBM. John Kennedy made political gains in the 1960 presidential election by exaggerating the "missile gap" issue. The Cuban Missile Crisis two years later brought the threat home as the Soviets set up missiles in Cuba, only miles from American shores.

The close call of the Cuban Missile Crisis led to the beginnings of talks about slowing the arms race. By 1970 135 nations signed a Nuclear Nonproliferation Treaty in an attempt to limit the spread of nuclear weapons.

Part of M.A.D: The Cold War exhibit

The Cold War