The casino – with its flashing lights, throngs of people and the sound of coins clinking – is a mesmerizing place. Gamblers come to gamble – and to win a jackpot – but it seems like something else is also at work: the desire to cheat or steal, rather than simply try random chance. That’s why casinos spend so much time, effort and money on security.

In the 1990s, casinos dramatically increased their use of technology to monitor everything. Chips with built-in microcircuitry enable the casinos to know exactly how much each bet is being wagered minute by minute; roulette wheels are electronically monitored so that any statistical deviation sticks out like a sore thumb. Security workers in a room filled with banks of screens can see all of the action, and they can even adjust their focus to zoom in on suspicious patrons.

Despite all the surveillance, casino patrons are an interesting bunch. On the surface, they’re a pretty diverse group: some are regulars who strut around with confidence and expect to win big; others are trying to make back the money they lost the last time they were there. But they all share one thing in common: they’re having a great time. Music is blaring, and the atmosphere is upbeat. People are talking and laughing, and the excitement is palpable. Sure, there are some tutting and finger-wagging when things don’t go their way, but for the most part it’s a happy crowd.

One of the reasons for this upbeat mood is comps – free goods and services that are given to casino “good” players, depending on how much they spend. These can include free hotel rooms, meals and show tickets. Some casinos even offer limo service and airline tickets for their biggest spenders. If you can get a good deal, it can keep you at the casino longer and gambling more, which in turn leads to higher profits for the casino.

Martin Scorsese has never made a movie quite like Casino. It’s a long film at just over three hours, but it never lags or runs out of steam. Unlike other Vegas movies that skim the surface of Vegas, Scorsese’s Casino shows its seamy underbelly: the intricate web of corruption with tendrils reaching into politicians, Teamsters unions and the mob in Chicago.

The movie isn’t without its flaws. Some of its truly hellacious violence, including a torture-by-vice sequence with a popped eyeball and a sound-designed baseball bat beating, had to be trimmed for an NC-17 rating. But, overall, Casino is an unflinching look at the seedy underworld of Las Vegas, a world that entangles the opulent and the dangerous with an almost cult-like devotion to chance. It’s not a movie for everyone, but it is definitely worth checking out.