Have you ever wondered why this hotel does not have a 13th floor, or why should you throw salt after you spill it? Here is the story behind some of the most common superstitions.
Some superstitions are so common that it is easy to forget that they are kind of strange methods. If an alien were to visit the earth, many people could not explain to them why we reflexively say "bless you" when someone sneezes.
But if you follow these traditions or not, it is really fun to find out where they come from. Everyone has a story behind it, so keep reading for some cool trivia that will impress your friends!
Why We Knock on Wood
The first recorded evidence that people say "Touch wood" (the British version of "Knock on wood") comes from the 19th century . However, the exercise is much older than that, and there are some contradictory narratives about where it came from.
Some believe that it is a pagan tradition from the Celts, who thought that trees were home to gods and spirits. They could have hit wood to thank the good spirits or to drive the evil spirits away.
Others practice the practice of Christianity, as the wood was also sacred in Christian cultures as the material of the cross. However, it is also possible that superstition is not so deep: some old children's games meant that you knocked or touched wood to become immune to losing.
Why we throw salt over our shoulder
If you dampen salt you can suddenly feel the need to throw a little over your shoulder – and if you don't , someone can remind you to do so. They can even say that you have to throw it over your left shoulder, not your right.
One possible explanation for this stems from the fact that salt used to be super expensive. If you wasted it, it was really the devil's work. Throwing a little over your left shoulder was supposed to blind the devil who made you waste it (Christians once believed that the devil was hanging behind his left shoulder).
One of the best known links to this superstition is in da Vinci's painting The Last Supper . Look carefully, and you will see that Judas has spilled the salt. Judas is the famous traitor to Christian tradition, so this depiction tied up salt to lie, betray, and the devil.
Why do we say "bless you" when people sneeze
Saying "Bless you" (or "God bless you") when someone sneezes is so common, it seems almost rude if you don't. But few people think about where this tradition comes from.
Long time some believed that a sneezing was an evil spirit that left the body or that the body was trying to get a spirit to leave. Saying "God bless you" helped protect the sneezer from the spirit again.
People also once believed that the heart briefly stopped under a sneeze, even though this has long proved to be false. However, the training can also come from the days of the plague during the Middle Ages. Legend has it that Pope Gregory made a decree that people would say "God bless you" for protection from the plague at any time someone sneezed.
Why we are afraid of breaking mirrors
Have you heard that a broken mirror means seven years of bad luck? You may not believe it, but the thought will probably still enter your head anytime you crack a mirror.
Because mirrors hold our reflections, people thought they were connected to our souls. This idea can be dated back to ancient Greece, where people believed that spirits could be found in the reflections of a still image of water.
When the mirror broke, the soul believed it was broken. Some legends held that this broken soul could not protect its owner from bad luck. Others said the broken soul would take revenge on its owner.
Why don't we go under ladders
The idea that it is bad to go under a ladder seems a bit more common: the person who works at the top of the ladder may perhaps drop a tool on his head, or even fall on you. But the superstition itself is more interesting.
Some judge this belief in ancient Egypt, where the triangle was kept sacred (pyramids, anyone?). Passing through a triangle shape was a large faux pas, and a ladder leaning against a wall forms a triangle.
Later, however, Christians adopted the same faith, which linked it to Christ's crucifixion. A ladder leaning against the cross at Christ's death, so they became unruly symbols that would cause misfortune to anyone who went under one.
Why do we not open umbrellas indoors
Modern umbrellas that open and close have not been around for a long time, so this is a superstition that may not be so old.
The first umbrellas from the 18th century were far from the ones we use today: they were heavy, difficult and used a system with springs and sharp metal bars to open.
Even today, we open an umbrella in a crowded room that can result in a poke in the eye. But imagine how it was with one of these earlier designs. From damage to broken objects, it is not difficult to see where this superstition came from.
Umbrella type designs that did not open and closed were also found in many previous cultures. In ancient Egypt, only royalty could use a parasol for protection from the sun. And in ancient China, leather umbrellas were a mark of nobility. So the superstition of opening an umbrella inside can actually have much older roots attached to the umbrella as a sacred royal object.
Why do we think number 13 is bad
People are afraid of number 13 so much that many hotels do not notice their 13th floor, instead go straight from 12 to 14. And Friday the 13th is considered a particularly unfortunate date.
This superstition goes back to the laws of ancient Mesopotamia, known as the Hammurabi Code. This code was skipped over the 13th law, but it is now considered a translation error, not a deliberate avoidance. Still, some cultures interpreted the omission as a sign of avoiding 13.  The number 12 has been widely regarded as an important number of many cultures: There is reason to have a 12-month calendar and count the hours by day in sets of 12. However, some thought that 13 was as bad as 12 was good.
Not only that, but old Nordic legends held that Loki, the trickster god, took the evil to the world when he was 13th guest at a party in Valhalla. Christianity also plays a role in this superstition. Judas not only knocked on the salt at the last meal: he was also the 13th guest to arrive.
Jadet Poonsittichok / Shutterstock
For some children there is no greater joy than finding a four-leaf clover. But why are these such coveted symbols of luck?
First, it is the simple fact that finding one is against the odds. Experts say your chances of finding one are 1 in 10,000 .
But even before scientists had calculated that number, there were people with four leaf clovers around. The old Celts sometimes carry them to keep evil spirits in the lake. In the Middle Ages, people believed that four leaf clovers could help them find and avoid dangerous fairies. And Christian lore once claimed that Eva picked a four-leaf clover that she was forced out of Eden.
Why We Hang Up Horseshoes
Have you ever seen a "happy horseshoe" hung above a door? This superstition is centuries old.
The ancient Celts began to hang horseshoes over their doors to ward off goblins, fairies and elves. The fact that horseshoes looked like the crescents was supposed to scare off these supernatural creatures.
Today some people think that horseshoes must hang with open ends, so happiness remains and does not fall out. But others believe that a horseshoe should hang together, so happiness knocks on the one who walks through the door.
Why We Want to Shoot Stars
We now know that "shooting stars" are not stars: they are meteors that burn up when they enter the atmosphere. But it does not prevent people from wanting when they see one.
This idea probably comes from Ptolemy, an astrologer in ancient Greece. He wrote that shooting stars was a sign that the gods looked down on the earth. If you saw one, it was the perfect time to want something from the gods.
Some central European cultures also believed that each person had his own star and a shooting star marked someone's death. While they would not wish for themselves, they could say a wish to the dying soul when they saw one, as a simple "walk with God".