It is the age of science. We have satellites in orbit, we can talk live on small portable devices between nearly any two points on Earth, and we can see more cat videos in one day than our forefathers could have dared dream of. Yet ancient superstitions still have a hold on us. Many superstitions seem insignificant or even silly—who really cares if you avoid a black cat’s path? There is a fine, and sometimes downright blurry, line between superstition, myth and urban legend. But not all superstitions are harmless. In some places, people believe that the body parts of albinos can bring them good luck. In the East African countries of Tanzania and Burundi, dozens of albinos have been murdered for this reason since 2008, according to the Red Cross. Superstition has also contributed to the decline of some of the world’s most magnificent animals: Several species of rhinos have been driven to near extinction because of demand for their horns, claimed to act as an aphrodisiac or even cure cancer. Superstitions often take the form of taboos, things you shouldn’t do. In some cases the superstition comes with its own remedy or counter-charm, its own mystical method for undoing the harm. For example, you may have bad luck if you spill salt on a table, but you can avert tragedy by throwing the salt over your left shoulder. Another old superstition cautions against opening an umbrella inside a house. To do otherwise invites back luck, either upon the umbrella opener or upon the household. It is not clear where this idea came from, though sources note that early umbrellas opened using a tight spring which was not reliable and could be dangerous if a finger was caught in it, or the umbrella opened suddenly or unexpectedly. In addition to being a common superstition, it is also practical advice: You do not need an umbrella inside, and getting a fully-opened umbrella through a door can be difficult. It is one of many admonitions against doing something mildly disruptive or destructive and unnecessary, such as breaking a mirror or walking under a ladder: It is probably harmless, but easily avoided by paying attention.