Tomorrow is Friday the 13th — do you know where your rabbit's foot is? Whether or not you believe in the superstitions behind the storied date, it's hard not to be impressed by their ubiquity. In fact, fear of this date is so widespread that it's actually cheaper to travel on Friday the 13th. Here, we take a look at why Friday the 13th has become a particularly dreaded day. But first, let's take a look at its basic elements: Friday and the number 13. Arguably the most vilified number (aside from 666), 13 has countless malevolent origins . It's been associated with death, Satan , and witchcraft. You may have heard the old wives' tale that, at a dinner table of 13 people, one person shall die — that superstition dates all the way back to Norse mythology . Meanwhile, Friday hasn't enjoyed a squeaky clean reputation, either. According to Snopes , Friday has been considered an unlucky day since the 14th century, thanks to Geoffrey Chaucer's reference to it in The Cantebury Tales: "And on a Friday fell all this mischance." However, the day's notoriety wasn't cemented until the 17th century — the literature of this time often linked Friday to meagre harvests, bad business, and disastrous travel. And, as we've mentioned in the past, Friday the 13th isn't the only unlucky day on the calendar. But what makes Friday and 13 such a lethal combination? It's actually unclear — the history around this supposedly unlucky date is murky at best (as it is with many other superstitions ). Fortunately, there are some possible leads out there. Here are a few potential origins of Friday the 13th as an ill-fated date: