Have you ever wondered why many buildings don't have a 13th floor? It's a little silly, but there is a very real reason.

It all starts with superstition. The number 13 has long been considered unlucky due to its association with evil, misfortune, and darkness. This belief likely stems back thousands of years, with some scholars pointing to the Last Supper as one of its origins (Judas was the 13th guest at the table). Others note that the number has also been associated with witchcraft, death, and betrayal throughout history.

When it comes to commercial and residential buildings, omitting the 13th floor is a common practice. Developers and landlords don't want to risk jinxing their building, so they either skip the floor or renumber it as something else. For example, some buildings with more than 20 floors will label the 13th floor as 14 or simply skip it altogether and call it a mezzanine or ballroom floor.

According to a 2007 Gallup poll, 13% of people were bothered by being given a hotel room on the 13th floor, and most who felt that way would request a different room. In the end, it's not just hotels that don't have a 13th floor—many apartment buildings and other buildings don't include one either.

While some people may not believe in the bad luck of the number 13, many still do, and avoiding it could boost a building's bottom line. For instance, some people are hesitant to rent an apartment on the 13th floor because they fear it will bring them bad luck, so they opt for other apartments instead. This can result in a loss of revenue for the apartment building, so it makes sense that some developers and landlords are wary of this possibility.