(CBS) -- Fear of Friday the 13th may be the biggest superstition of all time.

There are many reasons why 13 is considered an unlucky number, and some say Friday is a bad day because that's when the Crucifixion took place.

It also used to be the day for hangings. No one is exactly sure how fear of the combined date took root.

Click through these photos to see all of the superstitions.

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