What are some horrifying history facts or events that most people don’t know about?

1. The Bath School disaster in Michigan. In 1927, man by the name of Andrew Kehoe lost a seat for a treasury position. In retaliation, he blew up a school and killed quite a few children and some staff. He was an electrical engineer, and suffered a head trauma that may have caused his insanity. https://en.wikipedia.org/wiki/Bath_School_disaster
   — IFudgedTheMath


2. Engineers advised NASA to postpone the launch of the space shuttle challenger, due to concerns about the O-rings in the solid rocket boosters at low tempatures. They were over ruled, largely because the next launch window wasn't on a school day, and having students watch the first teacher launch to space was big PR goal. As everyone knows, that launch failed because an O-ring in one of the SRBs failed.
   — FallenShadow1000


3. The Great Siege Of Malta: “Mustafa had the bodies of the knights decapitated and their bodies floated across the bay on mock crucifixes. In response, de Valette beheaded all his Turkish prisoners, loaded their heads into his cannons and fired them into the Turkish camp.” https://en.m.wikipedia.org/wiki/Great_Siege_of_Malta
   — Fakezaga






4. Rosemary Kennedy's failed lobotomy, which made her mental capacity diminish to that of a 2 year old, and left her without the ability to walk or speak coherently.
   — Silly_Bun


5. Rwandan genocide, it lasted 4 months. Four fucking months and 1,000,000+ people died. Most died from being hacked to death by machetes. Edit spelling
   — Mumtaz3580


6. The Franklin Expedition in 1845 to find the northern passage, which would be a faster route when traveling and freighting cargo across the northern hemisphere to Asia and China. The ships got caught in the ice and therefore stuck there forever. The crew turned to cannibalism as a way to survive in the cold and stayed on the lower decks of the ships, where they'd eventually get very sick because of malnurishment. One of the ships were named "Terror" ironically, there's a book about it which of course puts in some supernatural elements to the story. I however think the real story is creepy in its own right. Imagine being stuck in the ice, it's cold as fuck everywhere, there's no food left and the nights are very dark. AMC is making it a series aswell, named after the ship; The Terror. It's directed by Ridley Scott, so it's bound to be unnerving. Trailer: https://youtu.be/rnN7Aad3c7A
   — FreePhilly






7. Taiwan's 2/28 massacre as well as the following White Terror, where an entire generation of intellectuals were wrongfully imprisoned or executed. Taiwan had the second longest period of martial law lasting 38 years, and only recently was it not taboo to speak about the events that transpired.
   — germ304