Not really something new that I learned today, but watching The Great War on PBS American Experience, it's amazing and slightly humorous to see pictures of hospitals full of patients and staff smoking cigarettes
My mother-in-law was an RN. She learned to smoke cigarettes in nursing school.
@ work... They used to have signs on the wall that would pivot and have to be flipped right side up. When flipped, it said: "No Smoking." We would have to flip them when tankers with petrol-chem, HAZMAT, etc... would transit the lock so nobody would smoke and we wouldn't go all boom! We would see who could drive the fastest with the golf cart and flip them all the quickest. I am surprised there was never a crash into the lock chamber.
Now? There is just "no smoking signs" everywhere, permanently mounted: "Danger! No Smoking During Lockage" What fun is that?