The year was 1803, and the world was a crazy place.

The continent of North America had been claimed and divvied up by France, Great Britain, and Spain, except for a relatively small sliver of land along the Atlantic coast that had recently declared itself the independent nation of the United States of America.

That new nation may have only been around for a few decades, but it was already looking to expand its borders and further secure its independence.

Across the pond in Europe, France's Revolutionary and Napoleonic Wars were taking a toll on its pocketbook, and the leader of the pack, Napoleon Bonaparte, was beginning to consider selling off some of its more expensive holdings.

Meanwhile, Great Britain's navy was the greatest (and largest) the world had ever seen, and they were amassing power and land like Imelda Marcos amassed shoes.

What was a continent to do?

Enter the Louisiana Purchase, a heck of a deal in which the United States bought the gihugic Louisiana Territory—828,000 square miles—from France for the tidy little sum of $15 million. Not quite the steal-of-all-time purchase of Manhattan, but not bad. Not bad at all.

Future prez James Monroe and Founding Father Robert R. Livingston had sailed to France planning on trying to buy the port of New Orleans and maybe some surrounding towns. They ended up instead with a territory that comprised a giant chunk of the middle of our present day United States.

Admit it, you've had shopping trips like that.

With one fell swoop (actually, more like three fell swoops), the Louisiana Purchase totally changed the course of all three of those countries we just mentioned.

The United States doubled in size just about overnight, and this set the stage for even more expansive borders in the future. France got the cash it needed to fund its new war efforts, and it got the distinct pleasure of taking Great Britain down a peg. Napoleon knew that if he didn't either keep Louisiana for himself or sell it to the Americans, Britain's international power would know no bounds. They were too strong and too rich, but the Napster figured that if the United States also got all big and rich, it would temper those powerful Brits.

And he was right.

Britain held on to its preeminent international position after the Louisiana Purchase, to be sure, but by the middle of the 20th century, it had become pretty clear that they were no longer the biggest dog on the block.

This deal—this one little deal, made up of three documents totaling less than 50 sentences—did all of that. And that makes the Louisiana Purchase not only the biggest real estate deal in history and one of the biggest international game-changers ever, but also, pound for pound, the most effective.

And if there's anything we history nerds love, it's an effective international game-changer.

Game on, Louisiana Purchase.

Two words: world domination.

Five more words: no one has done it.

And that's thanks in part to the Louisiana Purchase.

If it sounds a bit unbelievable that the sale and purchase of one itty-bitty piece of undeveloped land in the middle of an unexplored continent could halt wannabe world dominators in their tracks, have we got news for you: it wasn't an itty-bitty piece of land. It was huge. Roughly 828,000 square miles of huge, if you want to put a number on it.

Which we do.

And that tract of 828,000 square miles, even though it was largely unexplored and didn't have a lot of sprawling metropolises or a single Shake Shack, had something that no other piece of property did: serious strategic potential.

For France, Louisiana was one more stop on the imperialism express. Colonization was all the rage in those days, and France has always been known for being fashionable. By the time the year 1800 rolled around, the French colonial empire had its conquest-y thumbs all over the globe. Staking another French flag in North America kind of seemed like a natural extension of that.

For Great Britain, who had the best navy in the biz at that point, Louisiana was kind of scary. If it remained in French hands, the French empire would be unstoppably huge. If it became part of the United States, the fledgling country would for sure assert its new independence even more than it had during that pesky Revolutionary War. That could spell some trouble for British trade, expansion, and other economic interests. Great Britain didn't necessarily want Louisiana for its own, but it definitely had a vested interest in making sure the territory didn't go to anyone that could threaten its own position of influence and power.

And for the United States, which was in the passionate throes of new nation-ness, pioneerism, and sweet democratic freedom, the Louisiana Territory represented safety and security. If the United States didn't have to share its western border with a potentially hostile neighbor, it would be free to develop and trade and be all American and stuff without worrying about the threat of war. And, if the land out yonder was as fertile and green as some Americans had heard it was, the territory could also provide some serious economic benefits to the new and growing country. Hello, financial independence.

Chillin' here in the 21st century, it can seem mighty hard to imagine the United States being anything but American from sea to shining sea. But in the 1800s, America's current boundaries were anything but inevitable.

It took a lot of politicking, delegating, and plain old patience to get this deal done. And it took the specific skill sets of noteworthy dudes like Thomas Jefferson, Napoleon Bonaparte, James Monroe, Robert R. Livingston, and a handful of others. Oh—and it also took France and Britain going to war with each other.

The result was that the United States nearly doubled in size and secured its own geographic independence. This was one of the biggest factors that contributed to the United States becoming so rich, influential, and powerful in the centuries that followed, and it was also one of the reasons that certain other countries didn't become more rich and influential and powerful than they already were.

Obvi, it's impossible to say for sure what the world would be like today if countries like France, Britain, or even Spain had come in all aggressive-like and developed the Louisiana Territory as their own. But we feel pretty safe in saying that our history books would probably read a little differently than they do now. Had France kept possession of the territory, we'd probably be forced to eat a lot more crème brûlée and pain au chocolat. Which actually doesn't sound so bad, but still.

And really, "from sea to the shining Mississippi River" just doesn't have the same ring.