What is the secret of the "Star Wars" movies? "Star Wars: The Last Jedi" exploded into U.S. theaters with the second biggest opening weekend ever seen, behind only 2015's "Star Wars: The Force Awakens." How do the filmmakers keep us going back for more --- and more and more?

Any super-fan will tell you that the films are fun, timeless and relatable. And one reason they connect with us so well is that they're based in real-world history and economics.

"Star Wars" creator George Lucas carefully worked a lot of continuity into the series over the years, and he managed to succeed in tying all the stories together into a coherent universe that follows very familar financial practices.

Let's take a look at five economic lessons we can learn from "Star Wars," viewing the films in their current chronological order. And — warning — there may be some spoilers.

1. Fiat currencies (like the US dollar) have risks

Qui-Gon Jinn negotiates with Watto as Anakin Skywalker looks on from Star Wars Episode I
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Qui-Gon Jinn negotiates with Watto as Anakin Skywalker looks on.

You may or may not remember the scene from "Star Wars: Episode I — The Phantom Menace" where Qui Gon Jinn and little Anakin's owner, Watto, are bartering over the cost of a ship on the planet Tatooine.

Qui Gon: I have 20,000 Republic dactaries.

Watto: Republic credits? Republic credits are no good out here. I need something more real.

The dactaries are a "fiat currency." That's money that holds no intrinsic value but is valuable only because the government says so — as in the case of the U.S. dollar.

During inflation, fiat money can become worthless. You can look at Venezuela's free-falling currency, the bolivar, as an example. It's proof that fiat currency is not always the best way to go.

NEXT: 'Star Wars' offers advice on picking a bank.

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