Many superstitions are related to luck. Luck is the phenomenon that even improbable events can happen by random chance. Regardless if you avoid walking under ladders, turn back at the sight of a black cat or simply disregard the belief in bad luck, you have to admit having a lucky charm can't hurt... Right?  It is believed that hanging a horseshoe in a "U" shape above your door can bring good luck in and keep evil at bay. If you hang it downward, luck will follow you.  Horseshoes were originally made of iron, a material considered to ward off evil spirits. Traditionally they were held in place by 7 nails, considered to be the luckiest number. The number 7 is often considered lucky in Western culture and was very prominent in ancient cultures. It not only represents the jackpot on slot machines but is also the basis for many myths and folklore. The fear of the number 13 is called Triskaidekaphobia. It is believed that 10% of the United States has a fear of the number. Friday the 13th is considered to be bad luck. Hotels and skyscrapers often omit the number from their rooms and floors. Manufacturers will use other ways of numbering and labeling to avoid having to use 13. Bring yourself a little extra luck with this stackable ring.