This article was originally published on November 13, 2015.We're already a few hours into Friday the 13th, but there's still time to walk under a ladder, spill a ton of salt, or get on the bad side of a black cat. We hope you've taken all necessary precautions and, more importantly, are already preparing for the next Friday the 13th (hello, January 2017 ). However, you may want to start skimming your calendar for two other days that have come to be considered unlucky in certain regions of the world: Tuesday the 13th and Friday the 17th.The thing about Friday the 13th is that no one knows its exact origins — from connections to Babylonia to the crucifixion, all the way up to the relatively more recent Knights of Templar, there are quite a few strong theories. Some actually say that the ubiquity of the date's unluckiness among different histories just makes it all the more frightening. On the other hand, both Tuesday the 13th and Friday the 17th have slightly clearer origin stories, which we find strangely comforting. If we need to look out for a streak of bad luck, we'd at least like to know why it's coming for us.Below, check out when you might run into these days — and why they just might give Friday the 13th a run for its money. Next month, Friday the 17th is coming for us. The unluckiness of this date is only observed in Italy , home of those pesky Roman numerals: The number 17 in Roman numerals is XVII, which is commonly rearranged as VIXI , to evoke the Latin saying, "I have lived," or, more ominously, "my life is over." It's a bit of a stretch, but when we live in a world where people will refuse to fly on a certain day because of Babylonian law, we'll believe anything.Luckily, you get a bit of break after May and June. That is, until September 2016 , the next time the 13th falls on a Tuesday. The unluckiness of this day is a bit farther-reaching than that of Friday the 17th; superstitions about it are present in Greek, Spanish, and Latin American cultures. Concerns over this date stem from two major attacks on Constantinople, the capital of the Byzantine empire that ruled the Mediterranean region: first, in 1204 during the Fourth Crusade ; and second, the fall of the empire at the hands of the Ottomans. Both occurred on a Tuesday, and the final stand took place in a year (1453) with digits that add up to 13. As historians have concluded, 13 is simply a notorious number in Western cultures, wherever it appears. And in Spain and Latin America, Tuesday gained its infamy from an old folk saying that translates to "don’t marry, go on a boat, or leave your house on Tuesday."See, people have been changing travel plans out of fear for ages. No shame.