7. Doug Ammons
WHAT HE DID: In 1990, Ammons snagged the second descent of British Columbia's Grand Canyon of the Stikine, a roiling, 60-mile Class V canyon that's the pinnacle of expedition kayaking. Two years later, he came back to do it soloa feat that's never been repeated.
LEGACY: What Reinhold Messner (see No. 2) did for alpinism, Ammons did for paddling. The Montanan's solo on the Stikine still stands as the sport's ultimate test of commitment and perseverance. "I tried to do the hardest thing I could conceive of, in the purest style possible," Ammons later wrote.
CLOSING ARGUMENT: Piotr Chmielinski, hero of Joe Kane's Running the Amazon, shepherded the author down the first full descent of the world's longest river, in 1986, after seven of the 11 expedition members had given up and gone home. But there were still four of them.
6. Yvon Chouinard
WHAT HE DID: A keystone member of Yosemite's rocklegends from the fifties and sixties, who pioneered big-wall climbing and ground-up style, Chouinard put up major first ascents (including El Cap's North American and Muir walls), invented gear (reusable pitons and chocks), then built an iconic brand (Patagonia).
LEGACY: From how to release a fish to how to turn a business into a vehicle for environmental change to how to treat your employees, Chouinard spawned a new spirit of outdoor ethics. (And amassed a fortune.)
CLOSING ARGUMENT: Yes, you can find a more creative wall climber (Tom Frost), equipment inventor (Jacques Cousteau), or tycoon (Oakley and Red camera's Jim Jannard), but nobody's a triple threat like Chouinard.
5. Lynn Hill
WHAT SHE DID: After dominating sport climbing's World Cup circuit for the latter half of the eighties, the Detroit native returned to her trad-climbing roots in Yosemite and in 1993 claimed the first free ascent (i.e., using only her hands and feet and a rope) of El Cap's 2,900-foot Nose route.
LEGACY: Hill's stunning Nose ascent was like Billie Jean King defeating Bobby Riggsif Riggs was Roger Federer. The climb made its way into pop culture (see Jerry Maguire's breakup scene) and went unrepeated until Tommy Caldwell matched it in 2005.
CLOSING ARGUMENT: Kit DesLauriers's ski descents of the Seven Summits were just as daringbut not as surprising.