For nearly 20 years, the secret code to authorise the launch of US nuclear missiles was terrifyingly simple and noted on a checklist.
From 1962 until 1977, after John F Kennedy instituted Permissive Action Link (PAL) encoding on nuclear weapons, the combination to launch the destructive missiles at the pinnacle of the Cold War was just 00000000.
According to a report by Today I Found Out, the simple launch code was chosen by Strategic Air Command to make the weapons as easy to launch as possible in case of an emergency.
This was because there was initially concern that command centres or communication lines could have been destroyed in combat, preventing soldiers from getting the codes to launch missiles.
So, they simply left the security code for the weapons as eight zeros.
Dr Bruce G. Blair, who worked as a Minuteman launch officer in the 1970s, wrote that Strategic Air Command "remained far less concerned about unauthorised launches than about the potential of these safeguards to interfere with the implementation of wartime launch orders" in his paper called Keeping Presidents in the Nuclear Dark.
"Our launch checklist in fact instructed us, the firing crew, to double-check the locking panel in our underground launch bunker to ensure that no digits other than zero had been inadvertently dialed into the panel," Blair wrote.
In 1977, all the PAL systems were activated and the nuclear codes were changed - to something hopefully more complicated than 00000000.