The Launch Code for U.S. Nukes Was 00000000 for 20 Years

Steven M. Bellovin, a computer science professor at Columbia, uncovered a startling fact. The launch code for all U.S. Minuteman nuclear missiles for 20 years used the same code: 00000000. Bellovin discovered this after finding a 2004 paper by Dr. Bruce G. Blair, a former Air Force officer who manned Minuteman silos.
The codes — known as Permissive Action Links (PALs) — came to be following the 1963-1964 Cyprus crisis, when NATO countries Turkey and Greece wanted to nuke each other. The PALs were meant to give only the president of the United States the power to use such weapons. Apparently, this security feature was largely symbolic. For two decades, multiple presidents carried around a briefcase with the allegedly constantly changing codes, though it may as well have been filled with shredded newspaper.
The code itself wasn’t very secret, either. According to Karl Smallwood on Today I Found Out, Dr. Blair explained:

“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.”

All of this basically nullifies the plot to every military thriller film from the ’80s.
But it’s not like our government would ever accidentally nuke us, right? Oh, they already almost did that? Nevermind.