Urban legends have a way of reappearing.
That's part of their eerie magic—they can be converted to fit with different cultures and time periods, but they always seem to creep back into our consciousness.
These legends come from all around the world, and though many are not based in truth, it's terrifying to think that a real event could have inspired them.
1. England: Bloody Mary
There is no urban legend more famous than the story of Bloody Mary. It's easy enough to summon this evil ghoul: Just go into a darkened bathroom and say her name three times into the mirror, and supposedly a bloodstained woman will show up, either holding a bloodstained baby or promising to come and kill your children.
The actual Bloody Mary story may be based on Queen Mary I, a monarch born in 1516. Queen Mary took the throne at age 37 and married Philip of Spain. During her reign, Mary suffered from a miscarriage that is believed to be a case of "pseudocyesis," or "phantom pregnancy." Mary would suffer from this phenomenon twice during her life before dying at age 46, and this may be the location of the baby-killer image. (Of course, Mary also earned the nickname "Bloody Mary" by killing a bunch of Protestants).
However, Mary I may not have actually been the original inspiration for Bloody Mary. The "mirror witch" ritual could be based in traditions involving unmarried girls trying to catch glimpses of their future husbands, or they could also be based in old funeral rituals that viewed mirrors as portals between our world and the spirit world.