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One of the advantages of retiring early is that you can seek out travel adventures before you reach the expiration date of your knees. With that in mind, we asked travel writer Patricia Schultz to give us a list of rugged must-see destinations around the globe for energetic retirees. Schultz is the author of the best-selling 1,000 Places to See Before You Die and the newly released 1,000 Places to See in the USA & Canada Before You Die ($19.95 each, Workman Publishing).

Schultz promises that none of these trips is an extreme expedition along the lines of scaling Mt. Everest or rowing across the Atlantic. But they're not cakewalks, either. Schultz, 54, has tackled most of them in recent years, and her knees have yet to give out.HORSEBACK RIDING IN MONGOLIAEver since Genghis Khan encouraged his people to live by the sword rather than by the plow, Mongolians have been nomadic herders, holding to their horse-based culture and leaving vast tracks of their ruggedly beautiful land untouched. Experience the pristine countryside and the open-hearted hospitality of its people by riding through mountain-ringed valleys and the wide grassy steppes on Mongolian horses, legendary for their great stamina and ability to negotiate this difficult terrain.

Enjoy the welcome of remote encampments and stay in traditional yurts. Travel to visit Tsaatan families, an ethnic minority who herd reindeer and live in tents. Ride through forested mountains before ending up at Lake Hovsgol, an alpine lake bordering Siberia.

Organized trips might also include camel trekking in the Gobi Desert or white-water canoeing through the Altai Mountains, but if you're in Mongolia in July, you won't want to miss the national Naadam Games that take place across the country, with the capital city of Ulaanbaatar as ground zero. It's unbridled competition in the three manly sports of wrestling, archery, and horseback riding—the last one, little surprise, the hands-down favorite.OUTFITTER: Nomadic Expeditions, nomadicexpeditions.com, 800 998-6634EXPLORING IN BRAZILThe world's largest wetland, the Pantanal in Mato Grosso do Sul, is a landlocked river delta, an oasis of water and wildlife whose numbers and variety are staggering. It is an intact ecological paradise that is home to the largest concentration of fauna in South America—since much of the wildlife elsewhere has been hunted to extinction.

Unlike the Amazon, where wildlife can be hard to spot, the Pantanal is one big watering hole tailor-made for eco- touring. Spoonbills, chaco chachalacas, coatis, jabiru, rheas—chances are you've never heard of many of these creatures, let alone seen them. Others, such as wolves, anteaters, jaguars, and armadillos, you may have seen, but never this large.

Most of the South Dakota-size area is privately owned by huge fazendas (cattle ranches), and the spirit of the cowboys (called pantaneiros) prevails. Stay as a paying guest and join your cowboy guide on horseback at sunrise. Don't turn in until you witness nature's spectacle at night, when millions of fireflies create Christmas-light effects, and the eerie sounds of animals on the prowl are everywhere. OUTFITTER: Caiman Ecological Refuge, caiman.com.br, (011) 55 11 3706-1800FLOATING IN MADAGASCAR A river runs through this exotic land just slightly larger than Texas, off the east coast of Africa. With limited and primitive roads and almost no tourist facilities, the best way to experience Madagascar's rich diversity—30 species of lemurs, chameleons galore, and up to 10,000 species of flora—is traveling the Mangoky on a floating river safari into the island's remote southwest corner.

Quirky creatures and strange plants are everywhere on the 100-mile stretch from Beroroha to Bevoay. By some accounts, 80% of what you see is found nowhere else on earth. Rudimentary camps on river sandbars will seem downright luxurious when surrounded by the bio- diversity that explains why Madagascar is nicknamed the "eighth continent."OUTFITTER: Remote River Expeditions, remoterivers.com, (011) 261 20 95 52347CANOEING IN MINNESOTAMany states have lake districts worth noting. But none matches the Boundary Waters Canoe Area Wilderness, where the piney woods of Minnesota border Ontario.

More than 1,000 lakes, from 10 to 10,000 acres, promise more than 1,200 miles of mapped canoe routes and not a single road—a pristine labyrinth once used by the Ojibwa and later the 17th century fur-trading European voyageurs. Today it is part of the Superior National Forest and the largest U.S. wilderness preserve east of the Rockies.

Since the area is almost entirely off limits to power boats, canoers come from all over the world to paddle from lake to pristine lake, portaging (carrying the canoe overland to the next put-in) and setting up camp on different shores every night. The clear waters are rich with North America's greatest variety of game fish, offering anglers smallmouth bass, walleye, northern pike, and lake trout.

A strict permit system may create a bottleneck at the designated entry points, such as the charming town of Ely, Minn., but outdoorsmen soon dissolve into the wilderness, where they'll more likely be among moose, loons, and wolves than humans. Return in winter, and Ely becomes dog-sledding central.OUTFITTER: Williams & Hall Wilderness Guides & Outfitters, williamsandhall.com, 800 322-5837HELI-HIKING IN BRITISH COLUMBIAFrom July through September, this Canadian sliver of God's Country blooms into a nirvana for warm-weather hikes. The vast region just west of the Continental Divide is almost devoid of roads, so getting there can be half the fun.

A stylish fleet of helicopters ferries hiking enthusiasts into this wonderland of wildflowers, glaciers, rivulets, and snow-capped peaks. Guides are on hand for those treks that require technical skill or even mountaineering experience.

You'll find a smattering of comfortable backcountry lodges in the rooftop of the Cariboo, Bugaboo, Monashee, and Purcell ranges. (As many as a dozen stay open through the winter months when heli-skiing becomes the extreme sport of choice.) Start your morning with a hearty breakfast that stokes you for a day of exhilaration, and return to epicurean dinners, followed by a massage to pamper weary muscles.OUTFITTER: Canadian Mountain Holidays, canadianmountainholidays.com, 800 661-0252RAFTING IN WEST VIRGINIAMuch attention and ink are justly showered upon the white-water rafting experiences promised by the great rivers of the American West. But West Virginia offers some of the largest thrills-per-rapid ratios, in a landscape so inspiring it's referred to as the West of the East.

During the Fall Release of the Gauley River (when the dam at Summerville Lake is opened in early September), you'll encounter more than 50 Class IV and V rapids amid deep gorges and rough, wooded Appalachian terrain.

Steep drops with names like Heaven Help You and Pure Screaming may have you considering the Mountain State's other option, the New River, considerably calmer along parts of its scenic 53 miles. You could even bring along the grandkids, as long as you avoid the New River's lower stretch that drops 250 feet in 16 miles through gorgeous country. OUTFITTER: Wildwater Expeditions, wvaraft.com, 800 982-7238TREKKING THROUGH BHUTANA policy of limiting visitors means only 8,000 a year make it to Bhutan, one of the most remote and tantalizing corners of Asia. The last independent Buddhist mountain kingdom in the Himalayas feels light years from anything familiar. Television didn't even arrive until 1999. Boasting an untrammeled and breathtakingly beautiful countryside, 70% of its 18,000 square miles is forested, and its youthful, environmentally sensitive king ensures that the nation treats nature with respect.

Trekking is the natural way to see the country. Amid its countless highlights is the 8th century monastery called Taktshang, the Tiger's Nest, clinging to a sheer mountain ledge about 3,000 feet above the terraced Paro Valley. Hook up with a reputable outfitter who will introduce you to the whirling festivals and gracious residents of this Shangri-la now, before the first traffic light arrives.OUTFITTER: Asia Transpacific Journeys, asiatranspacific.com, 800 642-2742MOUNTAIN CLIMBING IN TANZANIAErnest Hemingway fell under Africa's spell when introduced to the allure of Mt. Kilimanjaro, its highest peak at 19,340 feet. No skill, ropes, or crampons are called for to scale its gentle grade, but one-third of Kili's trekkers never make it past Gillman's Peak, just 600 feet below the summit, because of altitude sickness.

Join an outfitter that allows extra time for proper acclimatization. To reach the mountain's dramatic, oddly flat top, you should opt for the more remote Shira Plateau. A battalion of porters bolts ahead to pitch tents at spectacular sites, set up camp, and get dinner cooking by the time you straggle in. The last night before the summit is spent at Crater Camp, at 18,750 ft. The views are surreal, with the plains of Kenya and Tanzania spread out for hundreds of miles, 3 1/2 miles below. Then you begin your descent. OUTFITTER: Thomson Safaris, thomsonsafaris.com, 800 235-0289BROWSING IN KASHGAR, CHINAVisit Kashgar, and it's easy to believe you are traveling back to the ancient Silk Road that linked the exotic goods of the East with Constantinople and the courts of Europe. China's westernmost city is 7 1/2 hours by plane from Beijing.

Stuck-in-time Kashgar has been a vibrant trading center for well over 1,000 years, and the Sunday market is not unlike what Marco Polo might have seen when he passed through in the 13th century. Marketgoers come to trade, sell, and haggle over sheep, camels, horses, dowry chests, fur hats, daggers, and hand-loomed carpets.OUTFITTERS: Geographic Expeditions, geoex.com, 800 777-8183WALKING THE NAKASENDO, JAPANIn the 17th century, the 315-mile Nakasendo—literally "the road through the central mountains"—was the principal route between Kyoto, the ancient capital of Japan, and Edo, a growing political and commercial center today known as Tokyo. You can follow in the footsteps of shoguns, samurai, and itinerant merchants and pilgrims along the best preserved, most scenic, and historically rich 63-mile stretch of the Nakasendo.

Luggage goes ahead by car while walkers put in some 15 miles a day, passing through small villages and along scenic passes. The ancient feudal byway is lined with family-run inns, many of which date from the early 1600s. Offered together with other treks that vary in intensity, the Nakasendo is led by American and British professors from Hong Kong who promise a fascinating and intimate peek into Japan both today and during the Edo period (1603-1867), when the Nakasendo was at its peak.OUTFITTER: Walk Japan, walkjapan.com, (011) 81 90 5026 3638