Everybody knows that opening an umbrella indoors is supposed to be bad luck. But is there any truth behind this age-old superstition? Fortunately for those spending sleepless nights pondering this question, there is actually a wacky holiday dedicated to finding out the truth.

The aptly-named Open An Umbrella Indoors Day was invented in 2003 by a man called Thomas Knibb. Knibb allegedly hoped to defy silly superstitions by encouraging people to open their umbrellas indoors and observe the (non-existent) consequences.

The best thing about this bizarre holiday is that anybody can take part. Just follow these four simple steps:

Find an umbrella and check that you are, indeed, indoors. Position yourself clear of breakable objects and/or people who value their eyesight. Take a deep breath, grasp the umbrella handle firmly with one hand and open the umbrella with your other hand. Note any bad luck that occurs in the following days or weeks.

Note: People who take part in this holiday do so at their own risk.