Welcome to Patagonia and Chile's pristine Rio Futaleufu, a 100-mile-long cerulean stripe that roars out of the Andes with unbridled fury from Argentina, across the top of Patagonia to the Pacific. For the last two decades, the Fu has been a well-guarded secret among the elite rafters and kayakers of the world, and rightfully so. But the Fu's future might be in jeopardy. Chile has few environmental policies to protect such wild places, and plans for damming the Futaleufu to provide hydroelectric power have been floating around for more than a decade. Time may be running out for this awesome river that offers Caribbean blue water, lush old-growth forests, Andean glaciers, breathtaking mountain vistas, and wilder rapids than most North American rivers (like the Colorado). "If one canyon contained the best rapids from North America's classic rivers, it would not equal the Futaleufu," says  Hertz. And he should know. His company, Earth River Expeditions, pioneered the Fu, making the first commercial raft trips in the winter of 1992, and has since established itself as one of the premier rafting companies in the world. It runs rafting expeditions on the world's wildest rivers, from the Primrose in the Yukon, to the world's deepest canyon of the Colca in Peru, to China's great bend of the Yangtze. Hertz has been rafting for 28 years, but still marvels at the Fu. "There is no greater combination of white water and beauty," he says. And that combination makes for one hell of an adventure.

Let's face it, an increasing number of Americans have lost interest in spending their vacation relaxing on a beach somewhere or getting their thrills at amusement parks. All that time in conference rooms and cubicles has gone to our collective head and we need to get out in the air. More and more Americans are spending their vacation time hiking, or scuba diving, or white water rafting. The Travel Industry Association of America's first-ever adventure travel survey showed, incredibly, more than 50 percent of the U.S. adult traveling population has taken an adventure trip in their lifetime.That's a staggering 147 million people - 75 percent of those people in the past two years.

As adventure travel continues to grow, it becomes harder and harder to really find true adventure anymore. The rivers and trails in many of our national parks are overrun by people who want a little visceral, outdoor experience, reducing them to not much more than parking lots with great scenery. Rafting the Colorado through the Grand Canyon can often be an exercise in patience, with a gridlock of motorized boats, crowds of people, and a waiting list that stretches for decades.

But that isn't the case on the Fu. Patagonia offers an incredible absence of people. The region barely has roads, let alone cars to contend with. Southern Chile is an undiscovered eco-travel paradise. The glacier-crowned peaks of the southern Andes dominate every view and rival the majesty of the Rocky Mountains. Small rivers and streams offer unparalleled trout fishing. Primeval forests are everywhere. "It's like Switzerland. It's like the Grand Tetons. It's so many places rolled into one," says Aleen Steinberg, a retiree from North Carolina joining us on the trip. But once you get a glimpse of the river, it immediately becomes the center of attention.