We'd joke about the miners saving their canaries before themselves, but that's probably not far from the truth. These birds weren't mere chirping gas detectors to some men; they were treasured companions, so much so that some miners reported "whistling to the birds and coaxing them as they worked [and] treating them as pets." To be fair, we'd be the exact same way -- not just because we're sentimental, but also because it's generally sound advice to not piss off the thing keeping you alive.
Related: 5 Artifacts That Prove Ancients Were Some Sick M'fers
Some Ancient Library Books Are Laced With Arsenic
People in the past had absolutely no clue about the dangers of certain substances. They put lead in kids' toys, prescribed opium for everything worse than a stubbed toe, and shoved radioactive isotopes upside their genitals. It was all dumb as hell, sure, but at least you can kinda see the logic in some of those decisions.
Others? Not so much.
Earlier this year, a team of researchers at the University of Southern Denmark were studying three books from the 16th and 17th centuries when they noted that the pages were covered in a green pigment. Interested, they had the pigment analyzed ... only to find out that they'd spent god knows how long huffing arsenic. More specifically, a type of arsenic used during the 19th century, in part, to protect books from insects and vermin. This practice was discontinued after people made the connection that they sure seemed to puke their guts out and die a whole lot when they were around arsenic all the time.
University of Southern DenmarkYour lifespan is now five years shorter just from looking at this picture. Sorry!
Since arsenic doesn't get any less toxic with time, and it's extremely possible to be poisoned by touching it or even breathing within its presence (we weren't joking about the huffing thing), the books are now safely under lock and key in a ventilated cabinet. So whichever dumbass monk or librarian did this succeeded in their goal of preserving the books. After all, no one's getting their grubby little hands on these things now.
Related: 5 Baffling Discoveries That Prove History Books Are Wrong
Utagawa Kuniyoshi's Hilariously NSFW Woodcuts
There's a very good chance that you don't know the name Utagawa Kuniyoshi. You're sure as hell going to remember it after this, though.