Some they spotted in clearings not far from the main roads. Others were discovered after long treks. They even stumbled onto one while they were completely lost. "We would have been happy if we found five," says Lee Whittlesey. "Instead we found 240."

He's not talking about pocket-size fossils or rare woodpeckers but—incredibly—waterfalls. Together with fellow explorers Mike Stevens, 54, and Paul Rubinstein, 40, Whittlesey, 51, scaled steep cliffs and dodged grizzly bears on the way to discovering dozens of previously uncharted cataracts in the vast pristine reaches of Yellowstone National Park. That so many waterfalls could have gone unnoticed in a national park visited by around 3 million people a year "boggles the mind," says Dr. Judith Meyer, a geographer from Southwest Missouri State University who has studied Yellowstone extensively. "How could we have missed all these waterfalls? Yet now we know even more about a place we thought we already knew everything about."

Fact is, most visitors to Yellowstone stick to the main roads or designated hiking trails. But the park, which spans 2.2 million acres across Wyoming, Montana and Idaho, also includes a sprawling wilderness region roughly the size of Connecticut. It was by hiking into this dense, tangled and largely untraversed forest hundreds of times over 10 years that the trio surprised even themselves by finding waterfall after waterfall not listed on any map. Says Rubinstein, a tour guide at the park: "We think we've added more new geographical data to the U.S. map than anyone in the last half century."

Certainly they have lived the dream of desk-bound, would-be adventurers everywhere. Their quest began in 1989, when Stevens set out to see all 50 mapped waterfalls in Yellowstone. A Southern Californian whose parents first took him to the park when he was 3, Stevens teaches math at Los Angeles's Simi Valley High School, a job that has allowed him to spend his summers working as a Yellowstone guide. An avid hiker, he was joined in his expedition by Rubinstein, who was raised in the San Francisco Bay Area and who quit his job as an air-traffic controller in 1989 to become a memorabilia dealer and, like Stevens, a summer guide at the park.

The pair found a kindred spirit in Whittlesey, an Oklahoma City native, who gave up careers as a TV broadcaster and later as a lawyer to work in what he calls his "dream job" as Yellowstone's official archivist. It was while studying old historical documents and wildlife surveys for their trip to the 50 known waterfalls that "it started to dawn on us how much of the park was untouched," says Rubinstein, who adds that the wilderness region's in-accessibility—it is buried under snow much of the year—has discouraged all but the sturdiest of hikers from exploring its wonders. "We realized we could hike for one year and do all the waterfalls we already knew," says Rubinstein, who lives with Barbara Totschek, 31, a former flight attendant. "Or we could make it a bunch of years and really go looking for waterfalls."

They set out in search of their elusive treasures whenever their schedules permitted and usually traveled in pairs. Every now and then they had a close encounter with lightning or grizzly bears. One time "we had a grizzly on a dead run 40 yards in front of us," remembers Stevens, who is single. "I woke it out of its nap, and it ran right across our path. The hair on my arms was sticking up for an hour after that." The payoff for all their troubles includes several falls that Whittlesey—who is married to Tamela, 39, a Yellowstone reservations coordinator and the mother of their daughter Tess, 8-believes they were the first non-Native Americans ever to lay eyes on.

Since publishing a small-press guidebook about their finds last year, they have discovered nine more hydraulic marvels—and estimate there are "dozens if not hundreds more out there," says Stevens. But while all three men will keep chasing waterfalls, they feel immense pride at having already staked out a place in Yellowstone's fabled history. "The thought that this park I love so deeply and care about so much might one day remember me fondly," says Stevens, "is simply wonderful."

Alex Tresniowski
Vickie Bane in Yellowstone

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