The twinkling lights, tantalizing beeps and bops, and the rapid thunk of a winning payout; these are a few of the alluring qualities that have led slot machines to becoming the most popular game for nearly all casinos worldwide. Simple to play and understand yet providing hours of entertainment, slot machines account for roughly 70% of US casino income.

While the first mechanical device similar to the modern slot machine was devised in Brooklyn, New York in 1891 by Sittman and Pitt, the first actual slot machine was created in San Francisco, California by inventor Charles Fey. Fey’s machine was the first to use three spinning wheels containing five symbols each and similar to modern slot machines, a match of three symbols on Fey’s device was a win. The true selling point for Fey was that his machine was the first to provide automatic payout, a technical possibility due to the limited nature of potential combinations.

Fey’s machine, known as Liberty Bell due to the Liberty Bell symbols used on the drums, enjoyed immense success and ultimately warranted such a high demand that competitors began creating their own copies to sell. By 1908, Liberty Bell machines (or their derivatives) were installed in the majority of locations where gamblers were thought to frequent, such as saloons, brothels, and smoke shops.