SHAGGY RIDGE TREK [PAPUA NEW GUINEA]
If you were to drop off the face of the earth, you'd probably land in Papua New Guinea's steamy Finisterre Mountains. Rising 13,000 feet out of the sweltering lowlands, the mountains' flanks are choked in jungle thicket that few have ever fully explorednot even the locals. Be among the first. Hike and camp for seven days on tangled game trails and World War II supply routes to Shaggy Ridge, an airy fin of rock 4,900 feet above the Bismarck Sea. Be prepared to answer a barrage of questions from Papuan villagers who rarely, if ever, see outsiders. OUTFITTER: World Expeditions, 888-464-8735, www.weadventures.com. WHEN TO GO: August, September. PRICE: $2,150. DIFFICULTY: strenuous.
THE ULTIMATE FLY-FISING ADVENTURE [MONGOLIA]
You've got much more than a fish on when you've nabbed a taimen, a specimen that regularly grows to five feet long and dines on prairie dogs and ducks. If you're not up for hunting the world's largest salmonid for a full week on the Bator River, you can cast for lenok, the brown trout of Mongolia; ride horses or mountain bikes; or just enjoy the good life in your ger, a woodstove-heated yurt with two beds and electricity. Outfitter: Sweetwater Travel Company, 406-222-0624, www.sweetwatertravel.com. When to go: May-June, August-October. Price: $5,200. Difficulty: easy.
RAFTING THE FIRTH RIVER [CANADA]
Caribou know no boundaries. Every June, the 150,000-strong Porcupine herd leaves the Arctic National Wildlife Refuge and migrates into the Yukon's roadless Ivvavik National Park. And because the Class II-IV Firth bisects the park, you'll be awestruck when thousands cross the river in plain view. Other big game are afoot, toomusk ox, barren land grizzlies, and wolvesand in such high concentrations that the region is often referred to as North America's Serengeti. With long Arctic days and three- to four-hour river sessions daily, you'll have plenty of time on this 12-day trip to hike the gently sloping 6,000-foot Brooks Range and fish for arctic char. Outfitter: Rivers, Oceans, and Mountains, 877-271-7626, www.iroamtheworld.com. When to Go: June. Price: $3,995. Difficulty: moderate.
RIO NEGRO & AMAZON ADVENTURE [BRAZIL]
The upper Rio Negro is your portal back in time on this 11-day adventure that plumbs the deepest, darkest corners of the Amazon Basin. From the former Jesuit outpost of Santa Isabel, you'll motorboat on the Negro's blackened waters through virgin rainforest, camping alongside Tucanos Indian settlements stuck in a 19th-century time warp. Off the water, you'll trek with native Brazilian guides into the rugged tepuis (3,000-foot plateaus), prowling for medicinal herbs used by local shamans. Resist the urge to swim: Football-size piranha call the Rio Negro home. OUTFITTER: Inti Travel and Tours, 403-760-3565, www.discoveramazonia.com. WHEN TO GO: year-round. PRICE: $2,750. DIFFICULTY: easy.
RUNNING THE KATUN RIVER [RUSSIA]
If you're looking for bragging rights to a truly remote river, consider the glacier-fed Katun. This 90-mile stretch of whitewater drains from the southern slopes of the 13,000-foot Altai Range, dropping fast through alpine tundra, 300-foot granite canyons, and continuous sets of Class III-IV pool-drop rapids. After a long river day, your evening entertainment at camp consists of traditional Russian dancing and a steamy riverfront bana (sauna). Outfitter: Bio Bio Expeditions, 800-246-7238, www.bbxrafting.com. When to Go: July. Price: $2,800. Difficulty: moderate.
COAST TO COAST IN BALBOA'S FOOTSTEPS [PANAMA]
Cross a continent in less than two weeks? Improbable but true when you retrace the route 16th-century conquistador Vasco Núñez de Balboa used to transport riches across the Isthmus of Panama. Five days of hiking, from the Caribbean village of Armila through the Darien Biosphere Reserve, take you to the Chucunaque River, where you'll board dugout canoes and navigate a maze of flatwater channels past Ember Indian settlements. Four days later, you'll find yourself on the other side: a wide stretch of beach where Balboa "discovered" the Pacific in 1513. OUTFITTER: Destination by Design, 866-392-7865, www.destinationbydesign.com. WHEN TO GO: May, December. PRICE: $3,290. DIFFICULTY: moderate.
SHAGGY RIDGE TREK [PAPUA NEW GUINEA]