The energy on a casino floor is something Las Vegans know well: anxious players, flashing lights, ringing bells, bemused dealers and the communal celebration when a jackpot is hit. It’s palpable, visceral and electrifying. Annually, it draws millions of tourists and locals alike, pumps billions of dollars in revenue into state coffers and anoints us all with a certain badge of honor.

Yes, this city is among the greatest amusement parks many adults have ever seen.

One of the biggest contributors to this energy, and a hallmark of the Las Vegas experience, is the omnipresence of slot machines. They welcome you at the airport, greet you at the supermarket and flood the casinos with joyful, colorful stimuli. They signify that you’re here — and that it’s time to play.

Like so many other gaming traditions, slot machines have a rich history and a complex evolution that have brought us to the machines we know and love today.

The very first slot machines

One of the first was conceived in Brooklyn in the late 1800s as a five-reel machine based on poker, with 50 playing cards featured. For a nickel, players would be given one spin wherein they’d pull the lever and hope for a good hand to populate across the reels.

The game was immediately and immensely popular but because there were so many possible winning combinations, manufacturers struggled to find an effective automated payout method. The bars that kept the machines often would “pay out” with nonmonetary prizes, such as free drinks or food.

Meanwhile, across the country in San Francisco, Charles Fey invented a simpler machine that more closely resembles the modern slot machine. The Liberty Bell machine featured three reels with five symbols: the Liberty Bell, horseshoes, diamonds, spades and hearts. This made an automated payout method possible, and the machines began their progression toward mass manufacturing.

The automated payout also allowed the machine, and subsequent other “bell” machines, to be used by a wider variety of establishments, including barbershops and bowling alleys.

Gambling for gum

Trade simulation machines were also popularized during the turn of the century by the Bell-Fruit Gum Co., which created machines that awarded pieces of chewing gum. These machines are what brought the cherry and melon symbols to modern slot reels, as well as the BAR symbol, which was the company’s logo at the time.

Electronic machines and video slots

The first electromechanical slot machine was created in 1963 by Bally and the first video slot machine was produced soon after, in 1976, by Fortune Coin Co., based in Las Vegas.

Debuting at the Las Vegas Hilton, video slots soon found their place among the Strip properties alongside mechanical and electromechanical machines. IGT purchased Fortune Coin Co. and its video slot machine two years later.

With the advent of electromechanical and video slots, the machines quickly evolved from the basic “one-armed bandits” to a more sophisticated and interactive play structure. These technological advances allowed for a wider variety of machines, larger jackpots, enticing themes and significant bonuses and bonus play options.

When online gambling hit the scene in the early 2000s, many slot manufacturers began producing machines to mimic the interface — and capabilities — of their online counterparts as well.

Today’s slot machine

Video graphics, LED lights, complex play structures and branded themes aren’t the only changes the industry has observed. In fact, as slot machine technology has advanced with the times, so has the audience.

Highly popular since their creation, the mass appeal of slot machines continues to build and the Center for Gaming Research at UNLV reports that between 1984 to 2016, slot revenues in Nevada grew at double the rate of table games.

It’s likely that this trend will continue as payouts, bonuses and jackpots get higher with each play.

Some of Vegas’ most popular slot machines:

• Wheel of Fortune

• Megabucks

• The Wizard of Oz

• Betty Boop’s Love Meter

• Sex and the City

• The Hangover

• Game of Thrones