I was sitting in the terminal lounge at Rio’s Galeao airport as we wrapped up our journey through Brazil, trying to piece together the fragments of what we’d seen and heard: the state of the art jet factory churning out planes…the trucks hauling harvests out of the fields…the woman in the favella who’d launched a business in her garage.

But the images that were most persistent were those small things that individually don’t mean much, but together leave you with impressions and emotions. Little things—like the comment of the farmer who told me his biggest problem was that John Deere couldn’t make enough tractors, like the Chinese businessman who casually predicted Brazil would be the next economic tiger. I remember being astonished at the skyscrapers of São Paulo…how they seemed to stretch forever along the horizon. I remember the cars in the cities…how new they looked…the roads, how modern. I wasn’t expecting the proliferation of convenience stores, upscale shopping centers, the easy availability of wireless broadband, and the astonishingly narrow distance between so much material prosperity…and so much poverty.

I thought about a conversation I had with a Brazilian official a few days earlier. We have so much in common, he said—referring to our respective countries. We’re both vast places with tremendous opportunity, with a sense of destiny, a history of slavery, and a massive discrepancy between the rich and poor.

Henry Luce famously called the 20th century the American century—a period when the United States emerged from isolationism and asserted its growing economic and political influence on every corner of the planet. These days, it’s become fashionable to talk about the end of that era, a transformation from a unipolar to a multipolar world. China. India. South Africa. A resurgent Russia. A robust Europe. That’s all front page stuff.

But while everyone’s been focused on those changes, Latin America’s biggest country has positioned itself much as the US did a hundred years earlier. What we’ve seen as we’ve toured this enormous land is a place bursting at the seams with growth, fueled by massive amounts of foreign investment, a worldwide hunger for its natural resources. A Brazil that’s embraced market economies and is actively rethinking its institutions to exploit its growing wealth. A Brazil that’s literally feeding the rest of world.

And all this adds up to a Brazil that the rest of the world is becoming increasingly dependent upon.

It’s going to reach critical mass very fast—the financial world is already betting on it. Picture São Paulo as a banking center rivaling London, New York, or Tokyo. It’s easy to do. Imagine this place as a regional power broker, settling squabbles, serving as peacekeeper-in-chief for Latin America, providing a political model for neighboring countries. A wealthy nation with a sense of its moment, commanding a bigger place at multinational conference tables. This is within Brazil’s reach.

In fact, you don’t have to squint very hard at all to imagine that the 21st century belongs to Brazil. Though they’ll probably have to share it with others.

As our plane finally took off bound for Miami, the wing dipped over Rio for one more long look. That’s when it struck me that there was something incredibly absurd about the fact that these changes are taking place with so little comment back in the states. Most of my friends back home have no sense of a multicultural American superpower emerging south of the equator. At the moment, the story of Brazil rising almost certainly represents one of the best kept secrets about the direction of the world.

Of course, it won’t be a secret much longer.