This Sunday, the 40,000 competitors in the New York City marathon will battle blisters, stinging nipples and mental fatigue. But few will know the misery felt by Anita Allen.

Last April, the 52-year-old from Coral Springs, Fla., entered the Gobi March, a 155-mile race through northwest China. A veteran of more than 100 marathons, she made it through four of the race's six stages, and embarked on the fifth at dusk to avoid 125-degree temperatures. The event organizers assured her they would have water stations along an illuminated course. But when the sun went down, she saw nothing for miles and barely found her way to a checkpoint -- where there was nothing to drink.

For the first time as a runner, she quit. "I've never been afraid that I could die during a race, but I really thought that was a possibility," says Ms. Allen.

As if finishing a marathon wasn't tough enough, a growing subset of adrenaline junkies is upping the challenge -- augmenting their long-distance runs with jet lag, food poisoning, extreme heat and organizers whose idea of hydration is a can of warm Coke. Now that more Americans are entering distance races, and cities like New York and London have proved that marathons are spigots for tourism dollars, organizers world-wide are adding events. The global marathon calendar, which already includes races in Antarctica and Tanzania, is continuing to add hosts. Even Beirut will stage its annual marathon later this month, despite some damage to the course from this summer's Hezbollah-Israel war.

With foreign marathon tour packages running as high as $15,000, the events are a natural draw for well-heeled runners. Completing a race north of the Arctic Circle or scaling the 3,700 stone steps at the Great Wall Marathon in China is an exotic antidote to running with the hordes in Chicago or San Diego. The ultimate cocktail-party boast: Running 26.2 miles on every continent. Marathon Tours, a Boston company that packages trips to foreign races, maintains a "Seven Continents Club." Anyone can join for a one-time $100 fee, but about 160 members have now actually completed a marathon on all seven, double the number from 2003, says company president Thom Gilligan. "We're literally beating the bushes to find new events."

But there's not always glory at the finish line. Or any finish line, for that matter. At events in far-flung places like Mongolia and Coban, Guatemala, scores of U.S. runners are sidelined by unfamiliar climates or overambitious itineraries. This summer, about 20 U.S. racers were stricken with stomach problems before or after the Safaricom marathon, held in the Lewa Wildlife Conservancy in Kenya. In Hong Kong this February, the annual marathon was delayed by 15 minutes when the city's pollution index soared: Some 4,000 runners required treatment, 22 required hospitalization and one runner died.

Runners are also getting in touch with the locals without breaking stride, returning home with tales of cigarette-smoking racers or, in one case, a boy who tried to sell runners a goat. At the Sahara Marathon, held annually since 2001 in far-west Algeria, runners stay in tents with Saharawi refugee families, and must rely on water that's been trucked in from 20 miles away. "It's not something for someone who wants a pleasurable trip in Europe with heated towels," says Jeb Carney, a foreign-policy consultant in Haymarket, Va., who helped create the event.

Sue Rudolph found a few details got lost in translation. At Spain's San Sebastian marathon in 2003, she was nearing the 20-mile mark -- in the rain -- when cars began speeding onto the course. The 56-year-old travel-agency owner from Huntington Beach, Calif., had no idea that the event stopped blocking traffic after 4 1/2 hours, compared with seven to nine hours for most city marathons. Ms. Rudolph and several of her clients got lost dodging autos and pedestrians in the Basque city. She ended up dropping out. "For the slower runners, it was an ordeal," she says. The saving grace: "I went back to the finish line, and they gave me a medal."

For big cities and developing-country outposts alike, a well-run marathon can be a boon for tourism: The Honolulu Marathon, which is sponsored by Japan Airlines, attracted over 17,000 Japanese runners and generated more than $100 million in tourist spending last year, according to a study conducted by Hawaii Pacific University.

While marathons go way back in international spots like London (1981) and Kosice, Slovakia (1924), more locales are adding them. The Association of International Marathons, comprising race directors from the world's biggest events, counts about 240 members, up more than 40 percent from five years ago. The list of races recently sanctioned by AIMS includes events in Mumbai and Dubai. Tokyo, which has long held a women's marathon, is staging its first co-ed version next February.

Such travel doesn't come cheaply. One Antarctica race, run by Irish adventurer Richard Donovan and scheduled for next month, costs $15,000 per person, which includes transport on a Russian cargo plane from Chile. Spots at another race on the continent, Marathon Tours' Antarctica Marathon, start at $5,200 a person. The itinerary for next January's race includes a 44-hour sea voyage across the Drake Passage, one of the planet's most treacherous stretches of water. (In 2003, the group's return passage to Argentina was delayed by flash storms and 30-foot waves, and many runners were late to catch their flights home.) Even so, company president Mr. Gilligan says all 220 slots for next year's race have been sold, with a waiting list for the 2008 trip. "Runners are Type A personalities -- fun in the sun doesn't do it for them," he says.

Fun in the sun didn't quite describe Michael Rooney's race in Tanzania in February. The 34-year-old lawyer from Manhattan went to the East African nation for two reasons: to visit his friend, a volunteer for the United Nations, and to indulge his newfound passion for running by completing the Kilimanjaro marathon, held on a course near the mountain's base. To prepare for the African sun, Mr. Rooney wore "tons" of extra clothes during workouts and hit the sauna at his local gym after running on the treadmill.

After taking a 24-hour trip from New York, he spent a few days in Dar es Salaam and acclimated himself with a few short runs there. He realized his training regimen had not prepared him for the dusty streets, blasts of warm wind and exhaust that spewed from all the old cars on the road. Then, the night before the marathon, Mr. Rooney went with another runner to a local "Italo-Indian" restaurant to load up on carbohydrates -- namely ugali, a cornmeal porridge that's a staple of Tanzanian cuisine. "It basically has the consistency of clay," he says.

The next day, he was barely able to run because of terrible stomach cramps and eventually, diarrhea. Afraid to drink local water, he opted for the cans of cola event organizers put at the aid stations. "Nothing like running in 90-degree weather and slurping down a hot Coke," he says. Luckily, he had stashed some toilet paper into a pocket in his running shorts, and found refuge at an outhouse he spotted on a farm near the 18th mile of the route. Finally, toward the race's end, a local boy pestered him in Swahili, until another runner shooed the youngster away. "He was trying to sell us a goat for about $3, which apparently was not a good deal," says Mr. Rooney, who eventually completed the marathon. "London would be a helluva lot easier."

Racers who compete internationally have to deal with usual matters of fatigue and injuries, of course. They're also susceptible to viruses and bacteria, because their bodies are drained from the combination of travel and exertion. There's also the potential for psychological letdowns for runners who travel great distances but fail to complete the race. "There's often an emotional void for runners after these long, demanding events," says JoAnn Dahlkoetter, a sports psychologist based at Stanford University, and author of "Your Performing Edge," a "mind-body" guide for athletes. Many marathoners "like the status and bragging rights" of running in exotic places, so failures are magnified. "Once you start traveling, it's like an addiction -- all these races become notches on your belt."

Of course, even many runners with horror stories say they cherish their foreign forays regardless of the hassle or expense. Numerous chat boards are filled with exhilarating race reports, and many serial marathoners look forward to bonding with like-minded runners. And around the water cooler, few things can trump a colorful marathon story. "I love running, and I love foreign travel -- anytime I get to combine the two, I'm a happy guy," says Jon Kroll, a 34-year-old information-technology manager in Redwood City, Calif., who's run events in Siberia and Iceland.

For New Yorkers Paul and Cassie Nelson, the Sydney, Australia, marathon will always have extra-special meaning: The couple ran it on their honeymoon in 2003. They met while training for the New York marathon, and in 2002, he popped the question at the finish line in Central Park. "If you think someone's good-looking after 10 miles, it's probably a good match," says Mr. Nelson, a 36-year-old political staffer. They've since traveled to marathons in London, Antarctica, Argentina and Kenya.

Amanda Salter, a third-year medical student at Georgetown, didn't find love when she ran the Dublin marathon a few years ago, but she did cope with an unusual obstacle: secondhand smoke, courtesy of some of the local runners. "I was getting passed by guys smoking cigarettes," she says. "Nobody seemed to mind."

She was also unprepared for the milder-than-usual weather, having prepared for the famously wet Irish climate by donning a windbreaker, turtleneck, sweatshirt, leggings and pants at the start line. By the end of the race, the 30-year-old native of Newport Beach, Calif., had tied most of the clothes around her waist. "I was told I looked like a bag lady," she says. She finished in a solid three hours and 42 minutes, and immediately joined her fellow competitors for the traditional victory refreshment. "No post-race food, no awards ceremony, just straight to the bar" for a pint, she says. "I had to acquiesce to local custom."

Race organizers and travel agents say they advise traveling runners to do most of their sightseeing after a race, and to avoid any foods that might have been washed with local water. As a precaution, many traveling marathoners also take their training foods and drinks with them abroad. And Mr. Carney, one of the founders of the Sahara Marathon, says he always keeps "a couple Cipros in my pocket" to take at the first sign of stomach trouble.

Though that, too, can have unintended consequences. Michael Schwartz, who runs a San Francisco company that makes research development products for pharmaceutical companies, went to Australia last December for an Ironman event. At the airport in Sydney, he was questioned repeatedly by security about a big container of white carbohydrate powder he brought to supplement his running drinks. "It took me a while to convince them it wasn't anthrax or cocaine," he says.

On foreign soil, it doesn't hurt to have a little help from a friend. Earlier this year, Tyler Burke ran the Rome marathon in part because his longtime girlfriend, Annie Donohue, had done it in 2002. During his training, she helped him prepare for the volume of the raucous fans, the pain of running on cobblestone streets, and even the lack of the energy gels or bars that are a staple at most U.S. marathons. "They did have plenty of sugar cubes and apple slices," says Mr. Burke, 26, who tracks fund-raising for the Leukemia and Lymphoma Society in New York.

But Mr. Burke was shocked to find that race volunteers only offered sparkling water, rather than the bubble-free version preferred by most Americans. Turns out he was just missing the magic words: Ms. Donohue forgot to tell him to say "non gazzata," the Italian term for water without gas, to the volunteers. "I guess I withheld a very critical piece of information," she says. "But it wasn't on purpose."

Run for Your Life

Here is a look at some upcoming running events in far-flung locations.

EVENT/LOCATION/DATE: Beirut International Marathon, Lebanon; Nov. 26
EXPECTED GBP OF PARTICIPANTS: 15,000
CHALLENGE: Hilly course, hard-to-find flights
COMMENTS: This urban course passes through several areas and buildings -- including the Chiah neighborhood and Old Saida Road -- that were hit during bombing this summer. But local organizers eliminated "horror hill," a steep climb under George Haddad Bridge that used to be a course feature near the end of the race.

EVENT/LOCATION/DATE: Reggae Marathon, Negril, Jamaica Dec. 2
EXPECTED GBP OF PARTICIPANTS: 600
CHALLENGE: 5:15 a.m. start time
COMMENTS: The pre-race meal, billed as the "world's best marathon pasta party," is catered by several chefs from the resorts in and around Negril. The night before the race, there's also a "Village Bash" in the parking lot of a Burger King. Male winner gets the Bob Marley trophy. (Top female gets a Rita Marley award.)

EVENT/LOCATION/DATE: Standard Chartered Dubai Marathon, U.A.E., Jan. 12, 2007
EXPECTED GBP OF PARTICIPANTS: 2,000
CHALLENGE: Organizers call course "flat and fast"
COMMENTS: It was only a matter of time before this pulsing city joined the global marathon circuit. For the fourth edition of the race next year, organizers have drawn up a new course that incorporates the new Jumeirah Beach Road, so runners can take in all the highrises along the coast, including the distinctive, sail-like Burj Al Arab hotel.

EVENT/LOCATION/DATE: Antarctica Marathon, Feb. 24, 2007
EXPECTED GBP OF PARTICIPANTS: About 180
CHALLENGE: Freezing weather, shoe-sucking mud
COMMENTS: Runners are advised to look out for skuas -- large, low-flying birds known for their "fierecely predatory" instincts. Course also includes an ice glacier with a 17 percent grade. Race is organized by Boston-based Marathon Tours, with travel packages starting at $5,200/person.

EVENT/LOCATION/DATE: Kilimanjaro Marathon, Tanzania March 4, 2007
EXPECTED GBP OF PARTICIPANTS: 700
CHALLENGE: Dust, stifling heat
COMMENTS: This event starts and ends at a college stadium in Moshi, about an hour by plane -- or nine by bus -- from Dar es Salaam. Race shouldn't be confused with the Mt. Kilimanjaro Marathon, a different event that takes place in June; that race, now in its 17th year, loops around one course four times.

EVENT/LOCATION/DATE: Santa Claus Marathon, Rovaniemi, Finland June 30, 2007
EXPECTED GBP OF PARTICIPANTS: 500
CHALLENGE: 5 p.m. start time, to take advantage of northern "white lights"
COMMENTS: American runners made up the second-largest foreign contingent at last year's race, with 23 U.S. competitors making the trek. (Germany led all foreign groups with 77 runners.) Finnish organizers expect double the turnout from last year, largely because of increased exposure through the race's new membership in AIMS, the international association of marathon directors.

EVENT/LOCATION/DATE: Great Tibetan Marathon, India; Sept. 8, 2007

EXPECTED GBP OF PARTICIPANTS: 175
CHALLENGE: Running downhill in melting snow
COMMENTS: Much of the course is run on tough terrain of India's Ladakh Province, narrow dirt roads that often are wet from melted snow. Because of the altitude -- the race starts at 12,000 feet -- a large portion of the route is downhill. Bonus: Aid stations are staffed by Buddhist monks. Event was canceled this year due to political instability.

Note: Participation figures include runners competing in half-marathons, 10Ks or other segments of the main race.