Hang glider pilots Chris Bolfing and John Heiney launch themselves off Glacier Point and gently glide 3,000 feet down through the Yosemite Valley; marine biologist Alana Osaki weaves her way through the kelp forests of the Channel Islands.
Outside Moab, professional slackliners Faith Dickey and Andy Lewis walk across a two-inch-wide highline; just outside Canyonlands National Park, 73-year-old rancher, Heidi Redd, fights to preserve her historic cattle ranch.
Ice climbing Hyalite Canyon during the winter; rock climbing Devil's Tower in the summer; Yellowstone National Park.
Mountain-biking legend Lars Romig in Sedona; photographer Ian Ruhter; Becky Stanridge documents the last known herds of wild horses.
The Hudson River Gorge; a flight over Adirondack Park; cliffs in Shawagunk Mountains; New York City's Central Park.
The waters of Vieques' Mosquito Bay; an underground river; a hidden paradise for snorkeling with three separate ecosystems.
Professional kayakers Rush Sturges and Evan Garcia take on the falls along the Columbia River Gorge; Eddy Cartaya and Barb Williams venture deep into the caves of Mt. Hood; Bill Anders and Jennifer Gifford investigate Crater Lake.
Extreme cave diver Brett Hemphill swims deep Jackson Blue's underwater cave system; Afghanistan war veteran Danny Redmond explores a personal connection to one of Florida's Civil War-era shipwrecks; starting fires in the Corkscrew Swamp Sanctuary.