School children in the 1950s wore dog tags for identification in case of Nuclear Armageddon.

(click images)
No nightmares there, I'm sure. The program was started in North Carolina, but never went national (a shame). In the early 1950s, every NYC schoolkid from kindergarten to 4th grade was issued a tag.
OK class, incoming. Put on your dog tags, and get under your desks. Here ya go Mom, this charred log is your Suzy. Related: Check out these unintentionally funny retro nuclear bomb-vertisements.