If you've ever stayed in a Las Vegas resort and paid close attention to the elevator display, you may have noticed something unusual. After reaching the 39th floor, the next number isn't always 40—it can jump directly to 50.

At first glance, it might seem like a mistake, but there's actually a cultural reason behind it.

The missing floors are linked to a long-standing superstition known as tetraphobia, or the fear of the number four. This belief is especially common in several East Asian countries, including China, where the Cantonese pronunciation of the number four closely resembles the word for "death." Because of this association, the number is often considered unlucky.

The influence of this belief extends well beyond hotels. In China, people frequently avoid the number four when choosing apartment numbers, phone numbers, and even vehicle license plates. A study conducted by researchers at the University of California, San Diego, also found that mortality among Chinese and Japanese Americans increased on the fourth day of the month for certain heart-related conditions, highlighting the cultural significance attached to the number.

Las Vegas has welcomed large numbers of visitors from Asia for many years, particularly from China. To make international guests feel more comfortable, several casino resorts have adjusted their floor numbering systems by omitting floors 40 through 49 altogether.

One of the best-known examples is the Aria Resort & Casino, which adopted this numbering approach when it opened in 2009. MGM Resorts explained that the decision was intended to better accommodate East Asian guests. The company had previously made another culturally sensitive change by removing the giant lion entrance at the MGM Grand after some Chinese visitors felt that walking through it symbolized being swallowed, an image considered bad luck.

Several major Las Vegas resorts have adopted similar numbering practices, including:

Wynn Las Vegas and Encore.

Resorts World Las Vegas, whose Hilton and Conrad hotel towers omit floors 40 through 49, while the main casino building also skips the fourth level.

Mandalay Bay, which also renumbered additional floors following the tragic events of the 1 October shooting.

Palms Casino Resort.

Elara by Hilton Grand Vacations.

Interestingly, while the number four is widely avoided, the number eight is considered especially fortunate in Chinese culture because its pronunciation resembles a Cantonese word associated with wealth and prosperity. For that reason, many visitors believe that a room number containing an eight is a particularly lucky choice.

So, the next time you're exploring a Las Vegas casino, don't be surprised if the elevator seems to skip an entire set of floors. It's not a construction error—it's a reflection of cultural traditions that continue to influence one of the world's most famous entertainment destinations.