Do you avoid walking under ladders? Or knock on wood to prevent something bad from happening?

Superstitions are common but irrational beliefs that stem from a misinterpretation of scientific facts or from urban legends. Some are as simple as a schoolyard rhyme — step on a crack and break your mother's back — or as creepy as a black cat pacing at the end of a dark hallway. We asked folks around the world — including our foreign correspondents — to share the strangest superstitions and urban legends.

Here's what they said:

In Zimbabwe, if you are kidnapped by a mermaid (yes, they are believed to exist here) and your family sheds even a tear for you, the mermaid will never return you to your family. It's an old superstition, but I heard it at a wedding as recently as April this year. — Marko Phiri, Zimbabwe

In India, we have zillions of superstitions, like if you leave the house before being swept, you’ll never have a successful day. If you move after a black cat crosses your path, you’ll have a bad accident. I’m a 13th-day born, so I’m an unlucky and uncanny woman. If you cut your nails or shave on a Tuesday or Thursday, or wash your hair on a Saturday, you’ll invite bad luck. Broken glass, broken artifacts or broken mirror allow devils abode in your house. I don’t follow them but have to under the pressure of parents. My parents and grandparents told me about them. — Akanksha Prasad, New Delhi

In Mexico and elsewhere, they say that if you put two mirrors in front of each other, you open a threshold for the devil. — Joshua Partlow, The Washington Post's Mexico bureau chief

In Afghanistan, never allow the broom to touch the feet of anyone. If you do, one of your parents will die. — Tor Khan, Bethesda, Md.

Never shake hands or kiss across a threshold; you'll become enemies. Never wish someone “happy birthday” before the day arrives, and never celebrate a birthday in advance: it brings bad luck. — David Filipov, The Post's Moscow bureau chief

In the Philippines, you don’t go straight home from a wake. You need to make a pit stop somewhere to shake off the bad spirit — it can be a coffee shop or a fast-food outlet (usually Starbucks, McDonald's or Jollibee). When you get home you need to change your clothes outside before entering the house. The idea is to not let the bad spirit in or enter the house. In Tagalog we call the practice as “pagpag,” meaning "to shake off.” — Dario Agnote, Manila

Want to share yours? Complete the submission form below.