(Photo by Shimon and Tammar for the Washington Post)

In 1493, Christopher Columbus returned to Europe with a handful of revelations and a pocket full of corn seeds. He had learned about many things during his travels to the New World, but few were as exciting as the promising grain he had encountered for the first time. It was unfamiliar; it was delicious; it was, as Columbus romanticized at the time, "affixed by nature in a wondrous manner and in form and size like garden peas," and it could, if they learned to farm it properly, help feed a lot of people.

The only problem was that Columbus had left behind a fairly important bit of information. "He didn't take back the knowledge of how to process it," said Betty Fussell, the author of "The Story of Corn," which chronicles the grain's several-thousand-year history. "That might sound innocuous, but it probably changed the course of history."

Over the next few hundred years, most of Europe grew to misunderstand corn rather than embrace it. Meanwhile, across the Atlantic, the grain endured a different fate: It thrived, and eventually found its way to the very center of the American diet.

Today, the United States is the largest producer and consumer of corn — and by a long shot. Corn is in the sodas Americans drink and the potato chips they snack on; it's in hamburgers and french fries, sauces and salad dressings, baked goods, breakfast cereals, virtually all poultry, and even most fish. The grain is so ubiquitous that it would take longer to list the foods that contain traces of it than to pinpoint the ones that don't. "Our entire diet has been colonized by this one plant," Michael Pollan told National Public Radio in 2003.

But corn wasn't always so omnipresent. It took time for European settlers to warm to corn and, most importantly, a coalescence of fortunate events for it to sprout into an industrial behemoth.

[In defense of corn, the world's most important food crop]

The choo-choo grain

Until the 1800s, corn was eaten mostly by the poor. It was a cheap and prolific crop, consumed by farmers and fed to prisoners. And it was also used as a commodity. As Pollan wrote in his poignant 2006 book "The Omnivore's Dilemma," corn "was both the currency traders used to pay for slaves in Africa and the food upon which slaves subsisted during their passage to America."

But then came the industrial revolution, and with it three essential technologies that helped propel the grain from the diets of the impoverished to dining tables all over the country.

The first was an iron plow, which allowed farmers to sow deep into the soil, and on much larger scales. The Midwest was planted with corn on a commercial basis precisely because of this new, simple but revolutionary tool. Two other advancements had an equally large effect, even though they touched corn production more tangentially.

"One of the most important boons for corn might have been that the commercial farms in the Midwest grew up at the same time as the canneries and railroads," Fussell said.

Until then, corn was mainly distributed locally. But the rise of trains, which moved the harvest well beyond county limits, and the advent of canning, which meant it could keep for much longer, allowed farmers to grow with hundreds of thousands of mouths in mind. In the coming decades, the amount of land dedicated to corn grew incredibly quickly. It would be another half-century, however, until corn made its way to the center of the American diet.

[How to grill corn so you get it right every time]

Help from science and price

Corn is what Fussell calls a genetic monster, because it's highly adaptable and easily manipulated. And there is, perhaps, no better example of its mutant-like qualities than what happened shortly after the turn of the 20th century.

In the 1920s and 1930s, scientists discovered a way to boost corn production to a level that was previously unthinkable. They bred hybrid strains that had larger ears and could be grown closer together, which allowed farmers to produce a lot more corn without more land. The discovery, coupled with the introduction of new industrial fertilizers and more efficient farm tools, such as tractors, led to a thunderous rise in output.

In the following decades, "the number of bushels of corn per acre doubled, and then continued to rise each year," as Paul Roberts wrote in his 2009 book "The End of Food." Corn yields have risen ever since, with only brief interruptions due to sporadic droughts, interruptions that farmers are countering with further engineered corn.

Advancements in farming technology and science paved the way for corn's ascent in the American food system, but what has allowed for corn to seep into just about every food Americans eat today is that, above all, it is inexpensive.

"Corn has and always will be cheap, because it grows everywhere in the world," said Fussell.

At present, a bushel of corn costs about $4 — less than half the price of soybeans, and a good deal less than wheat. And the price is falling.

[Today's botany lesson: a graphic on corn sex]

What we grow, what we eat

The most incredible thing about the corn grown in America today is how little of it we actually eat.

Less than 10 percent of the corn used in the United States is directly ingested by humans. The bulk is either turned into ethanol, for use as fuel, or fed to the hundreds of millions of animals we raise. Cows, chickens, pigs and even fish, which are fed pellets made largely of corn, eat several times the amount of the grain consumed by people each year.

The relative cheapness of corn and general usefulness of it as a form of energy — both for living animals and living, more generally — have proved important enough that the government subsidizes its production to the tune of some $4.5 billion each year. The result is perpetuation of ambitious growing goals: Farmers, realizing that the more efficient they are, the more money they will get, grow more and more corn. The more corn there is, the lower its price, and the greater the incentive to use it in as many ways as possible.

To talk about corn without talking about the different varieties would be to overlook an important facet of its ubiquity in the United States. There are many types, but the most commonly eaten forms can be divided into three general categories.

The first, which is perhaps the most romanticized, is sweet corn. Sweet corn is what Americans grill in the summer, and boil or bake during the rest of the year. It's eaten on the cob. It gets stuck in your teeth. And it accounts for only about 1 percent of the corn grown in America.

Flint corn, which has a soft center and harder outer shell, is what most people know as popcorn. It became popular in the 1960s after Jiffy Pop, which cooked the kernels in aluminum foil on the stovetop, was introduced, and rose further in the 1970s and 1980s, shortly after the introduction of the microwave. Today, much like sweet corn, flint accounts for a steady but comparatively insignificant portion of the U.S. corn crop.

And then there's dent corn, a.k.a. field corn, the most important kinds. It accounts for the vast majority of corn grown in America today, as well as the vast majority of the corn Americans eat. It's in most animals we eat, because it's fed to most animals we raise for slaughter; it's in most of the beverages we drink, because high-fructose corn syrup, which is derived from flint corn, is the most commonly used commercial sweetener; it's even in our cheese, because our cows munch on it instead of grazing on grass.

It's largely invisible, in other words, but also virtually inseparable from the American diet.

"People have this kind of nostalgic understanding of corn," said Fussell. "They think of corn on the cob and popcorn. But the truth is that field corn is what we are really talking about when we talk about the dominance of corn in the United States."

"It's in almost every product in the supermarket today," she said. "That's no exaggeration."

In many ways, Europe still scoffs at the grain that defines the American food system. The old world is a wheat culture, Fussell says. But the truth is that corn's ubiquity in the United States has, in turn, boosted its popularity elsewhere. American-style processed food, which almost always relies on corn, touches countries all around the globe.