Here is the story I wanted to read about based on the headline. Post WWII, the U.S. government had given automobile makers a directive to include a spark gap in the rear-view mirrors of vehicles. If you were fleeing a potential nuclear event in your vehicle, this spark gap would then give a visual indication of the electromagnetic pulse from the detonation, giving the driver a valuable second or two to prepare for the slower-moving incoming shockwave. And that this little-known feature has survived in our mirrors up to this day, even though it is completely useless now with modern automobile's electronic fuel injection, etc. that would be rendered inoperable by the EMP.