If one walks underneath an open ladder it is said to bring bad luck. Sometimes it is said that this can be undone by immediately walking backwards back underneath the ladder.
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The superstitious symbolism of a black cat crossing one's path is dependent upon culture: some cultures consider this a sign of impending bad luck, while some cultures consider this a sign of impending good luck.
75
When you speak of bad luck, it is said that one should always knock on wood. Also knocking when speaking of good luck apparently helps with having good luck. This is an old Celtic tradition related to belief of wood spirits.
208
In some parts of England, rum is used to wash a baby's head for good luck.
71
There are numerous sailors' superstitions, such as: it is considered bad luck for a ship to set sail on a Friday, to bring anything blue aboard, to stick a knife into the deck, to leave a hatch cover upside-down, to say "pig", or to eat walnuts aboard.
70
In Asia, the digit 4 never appears in any Nokia handset model number, because 4 is considered unlucky in many parts of Southeast/East Asia.
78
Placing keys on a table is considered unlucky. (Sweden)
3
An acorn at the window will keep lightning out
93