Last week, the United Kingdom shocked the world by voting to leave the European Union. The move, dubbed "Brexit," seems confusing, not just to the rest of the world, but also to many of those who live in the affected country.

Although one might describe the European Union as something similar to the U.S. for Europe, with each individual member country being a state, it's a little more complicated than that, specifically because each individual country maintains some sort of autonomy. Also, apparently, member countries can decide to leave, although the UK is the first to actually do so.

The idea behind the E.U. is to consolidate Europe to give it an internal single market with a standardized set of laws that govern all member countries. It also allows for easy business between countries, with many even using the same form of currency, the Euro.

It sounds like a win-win situation, right? The UK, apparently, didn't think so, and now, it's stuck with a decision that leaves much of the rest of the world scratching its head. So, how did it happen?

Here's a simplified explanation from NowThis, using clips from The Simpsons:

The video is definitely biased in favor of "remain," although that vote lost when put to the test. The video uses Groundskeeper Willie to represent Scotland, which voted overall to keep the UK in the E.U. However, the best explanation comes from Lisa, who explains that the reason the "leave" vote won is because seniors vote in record numbers, and polls show that the UK's older citizens were in favor of leaving, while the younger generations preferred to stay.

What's done is done, though, and now, the UK has to deal with the fallout of Brexit. Some believe that a second referendum and vote should happen, particularly as the "leave" vote only won by a few percentage points. Some believe that it's just something that will never actually happen, especially now that Britain's political situation is so chaotic, thanks to Prime Minister David Cameron stepping down after the vote.

Whatever the case, though, the world is watching. Now, thanks to The Simpsons, people outside of Europe have a better understanding of how these things happen. It also serves as a warning to the rest of the world, especially the U.S., which has a major presidential election coming up this fall.