If you're the superstitious kind, you are probably avoiding black cats, cracked pavements and ladders today.
But why is Friday the 13th considered such an unlucky day?
Not a lot is known about how the day became so notorious, but one theory claims it has Biblical beginnings -- there were 13 guests at the Last Supper and Jesus died on a Friday.
The day is also mentioned in a book about Italian composer Gioachino Rossini, who died on Friday the 13th.
Or perhaps the day's creepy connotations stem from the events of Friday, 13 October 1307, when King Philip IV ordered dozens of Knights Templars to be arrested.
However it started, the idea now has people holding their breath while driving past cemeteries and not looking in cracked mirrors whenever the 13th day of the month happens to be a Friday.
The superstition even has its own difficult-to-say term -- paraskevidekatriaphobia.
Any month which starts with a Sunday will contain a Friday the 13th, and there can be up to three in a year. This is 2016's one and only dark day.
Four fun facts about Freaky Friday: