During this race, "you will almost certainly be attacked by a brown skua, a predatory bird that feeds on penguins," says race founder Thom Gilligan. "Runners look like large penguins to them." Marathon Tours & Travel arranges a complete itinerary for participants, which includes round-trip airfare from the U.S. to Argentina, three nighs in Buenos Aires and a 10-day cruise from Ushuaia along scenic channels and passages to the Antarctic Peninsula. Book now—spots fill up a year or two in advance.

For more information: The Last Marathon

Easter Island is facing one of the most extreme cases of deforestation in the world; thus, much of this small Chilean territory is a barren wasteland. "The route went out across the island—and it's very volcanic—but on the way back at the highest point, you could see about half of the coastline of the island," says longtime marathoner Ed Sylvester. "There is no vegetation, nothing. It's amazing to see what people can do to their environment." You'll have to fly to and from Santiago to reach Easter Island, so spend a few additional days in Chile's cosmopolitan capital once you've logged your running time.

For more information: Easter Island Marathon

Good thing you incorporated a Stairmaster into your training: The Great Wall Marathon has 3,700 steps to ascend—in each direction. But lucky for you, there is an eight-hour time limit. (Most marathons offer no more than seven.) The wall portion of the race is actually only a little more than two miles in length; the rest of the path travels through local towns.

For more information: Great Wall Marathon

You'll be glad to know the course for this marathon does not actually ascend the entire mountain, but you'll have a nice view of Africa's highest peak throughout the race. "The course is a 6.5-mile loop through the town of Moshi. It's a very nice marathon, but it's small—just a couple hundred people," says Marie Frances, the race's founder. "It's really a biathlon: Participants climb the mountain first. It takes five days up and down, then the runners rest for a day before completing the marathon." After the race is over, runners often like to explore the Serengeti or take a trip to Tanzania's crown jewel, Zanzibar.

For more information: Mt. Kilimanjaro Marathon

The world's highest peak also boasts the world's highest marathon. The race is held on the same symbolic date each year: The day the first human ascended Everest. "The Everest Marathon is truly a fabulous journey, which offers beautiful rock formation, cascades and canyons slightly hidden under the thin mists," says Bista Sushil, the marathon's event management officer. Before the run, participants camp at Everest Base Camp. On the way, expect to see oaks, pines, hemlocks, rhododendrons, Himalayan Tahr, Musk deer and Impeyan pheasants.

For more information: Tenzing-Hillary Everest Marathon

If you've always dreamt of going on an African safari, the Big Five Marathon offers you the chance to do just that— only, on your own two feet. "On the Big Five marathon, you can expect incredible natural beauty—from simple scenery, to a herd of antelope running alongside you." If the thought of being a tiger's lunch doesn't appeal to you, fear not: Park rangers watch over you the entire way. A similar race, the Safaricom Marathon, takes place in Kenya the same day.

For more information: The Big Five Marathon

Australia's premier running event will celebrate its 30th anniversary this time around; nearly 20,000 participants are expected. You won't get bored on this beachside run along the postcard-worthy eastern coast. If thinking of running a marathon in the height of summer in balmy Oz is a deterrent, fear not: It's the dead of winter on that side of the world (though conditions are still pleasant). Allow time for exploring the country once you're through. Maybe hop a flight to Cairns, from where you can explore the Great Barrier Reef.

For more information: Gold Coast Airport Marathon

It's most locals at this marathon, but Americans are known to enter this remote race, which is hilly but not nearly as cold as you might expect. Cliff Jennings, sales manager at Marathon Tours & Travel, urges visitors to explore the country afterward. "You can head to a town a little bit north of the Arctic Circle called Ilulissat," he says. "That's where you'll wake up to icebergs floating just outside your window." The Polar Circle Marathon also takes place a little further north in Greenland on Oct. 18, though due to its location, it's not the most reliable of races. (Inclement weather has led to cancellations in the past.)

For more information: Nuuk Marathon

When contemplating this run, remember what you learned in grade school: "Iceland's green and Greenland's icy." "This route travels through the quaint, cobblestone streets of the country's capital and along the waterfront. It's all in the city, but you wouldn't know it because it's such a pleasant run," Jennings says. After you've removed your running shoes, be sure and check out some of Iceland's highlights, like the Blue Lagoon just 25 miles west of Reykjavik and one of the many volcanoes and lava fields that characterize the island.

For more information: Rekjavik Marathon

Intrepid marathoners are taking note of the tiny South Asian nation, tucked discreetly between India, Tibet and China. Bhutan tourism is tightly regulated, but the race committee allots 300 spots for international entrants. Because the course rises to an elevation of nearly 8,000 feet, coordinators urge runners to train accordingly. Once the race is over, enjoy the Himalayas and the rest of this country's rugged, untouched terrain and ecosystem. If you miss this race, try for the second SaabSalomon Himalayan Kingdom Marathon, also in Bhutan, held in November.

For more information: International Sanction Marathon