Every four years we're treated to February 29, more commonly known as Leap Day.
It may seem a bit mind-boggling (where has this extra day popped up from, after all?) but when we've looked at the "science bit" it really is quite simple.
A common year for us here on earth has 365 days - and our extra Leap Day is designed to arrive every four years and bring our calendar year up to date with the solar year.
Our planet completes its orbit around the sun after 365 and a quarter days - meaning we accumulate an extra 24 hours every four years.
February was the month chosen to host the extra day, as it's the shortest month in the year. So now we know!
But since Leap Years were introduced by Julius Caesar there have been many superstitions or traditions observed by communities across the globe.
The most well-known is the tale that February 29 is the day for women to propose to men. Legend has it that St Brigid made this deal with St Patrick so the gender roles of men and women could be balanced - just as Leap Day balances out the calendar.
Following on from this. another tradition has said that any man who refuses a woman's proposal on February 29 must buy her 12 pairs of gloves. They would be used to cover the shame of her not having an engagement ring.