Why do many Las Vegas casinos skip floors 40-49?

Picture this: You’re riding an elevator up to the top floor of a Las Vegas casino and watching the numbers slowly trickle up to the 20th and 30th floors.

But, once you inch toward the 40th floor, something weird happens.

38… (beep) 39… (beep)

Then, 50.

Most Americans might be used to hotels missing a 13th floor, but why do some casinos not have 40th floors?

Simply put: superstition.

The fear of the number four, called tetraphobia, is common in many southeast Asian countries, namely China. In Cantonese, the word for four sounds like the word for “death.”

Fear and avoidance of the number four can be found throughout Chinese culture. Bloomberg reported in 2015 that the least-common number on a license plate in Beijing is four (drivers overseas get more choice in choosing their license plate numbers), and a 2001 study from the University of California at San Diego found that cardiac mortality in Chinese and Japanese people in the United States rose on the fourth day of the month — especially for those with chronic hearth disease.

With Chinese tourists being historically one of the largest groups of international visitors to Las Vegas, it makes sense why so many casino owners would want to avoid any faux pas.

When the Aria opened in 2009, MGM Resorts told USA TODAY the company made sure not to include floors 40 through 49 to appeal to east Asian guests. The company also removed the MGM Grand’s old lion head entrance in the mid-1990s after many Chinese guests said going through it felt like being eaten alive, Forbes reported.

Some Las Vegas properties that skip floors numbered 40-49 include:

— Wynn and Encore

— Resorts World, owned by the Malaysia-based Genting Group, does not have a floors numbered 40-49 in its Hilton or Conrad towers or a fourth level in its main casino property.

— Mandalay Bay, which also renumbered floors 31 through 34 and floors 56 through 59 after the 1 October shooting, where a shooter took 58 lives from a suite on the 32nd floor.

— The Palms

— Elara by Hilton

So, the next time you’re in a Las Vegas casino, watch your luck. And, if you can, stay in a hotel room with an eight, which sounds like a Cantonese word meaning “prosperity.”