An indigenous walrus-hunting camp brings signs of life to sparse slopes in Greenland. The self-governing Danish island is among the least densely populated major areas on Earth, according to the United Nations-a stark contrast to the boom cities that reportedly helped to drive Earth's population to seven billion on Monday.
Three times the size of Texas, Greenland is mostly covered by Earth's second largest ice cap. Not surprisingly, its 58,000 inhabitants cluster in coastal communities. "It's not likely that population will expand dramatically until there is more trade and international exchange," said Patrick Gerland, a population expert with the UN.
Some tourists, however, are beginning to seek out the planet's less populated spots—including Greenland.
Jonathan Tourtellot, founder of the National Geographic Society's Center for Sustainable Destinations, said Greenland primarily draws two types of travelers: "One is expedition cruise ships, and the other is flight excursions to a few different points in Greenland," he said. "There isn't much in the way of roads, so you have to move by either air or water."
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Photograph by David McLain, National Geographic
A wandering albatross has plenty of room to spread its wings in the Falkland Islands (map), a U.K. territory off South America that has housed a British naval garrison since 1833. With slightly less land than Connecticut, the archipelago is home to only about 3,000 people.
"Populations like the Falklands are in some ways artificial and sustained because of their relationships to a far away mainland," the UN's Gerlans said.
About ten times as many people visit the islands each year as live in the Falklands—a popular ecotourism stop, particularly for Antarctica-bound cruises, the Center for Sustainable Destinations' Tourtellot said. "It's a very interesting place, with wildlife and a beautiful landscape and a kind of odd little British society on an island that's so far away from everything else."
With roughly three million people living in a country nearly the size of Alaska, Mongolia averages fewer than two people per square kilometer (about half a square mile), according to UN statistics.
Most of that population is in urban areas, since development in Mongolia's vast deserts and grazing lands is hindered in part by drought and dust storms, leaving those parts of the country nearly as empty as they were in Genghis Khan's time.
"Mongolia, in a way, is hot as an adventure destination," Tourtellot said of a nation struggling to embrace tourism while developing other industries. "They are doing a lot of mining, so there is some concern about protecting what is otherwise a beautiful landscape and a place with some fantastic archaeological sites as well."
Green fields such as these near Laayoune are a rarity in Africa's Western Sahara (map) region. Only 0.02 percent of the land is arable in this former Spanish territory, which has been disputed since the 1970s and remains split between the government of Morocco and the Polisario Front. (See your Morocco pictures.)
Similar in size to Colorado, the Western Sahara is home to only about half a million people, largely clustered on the coast.
"If you look at the geographic conditions there, it's mostly desert, and some of the people living there can [also] be found in neighboring countries like Algeria, because a substantial number are nomads," the UN's Gerland said.
Adventure travelers may enjoy 4x4 desert driving as well as windsurfing and kite surfing along the coast. But the area offers little in the way of mainstream tourist infrastructure. What's more, the bitter fruits of long conflict—including land mines and the threat of terrorism—have kept most travelers away, the Center for Sustainable Destinations' Tourtellot said.
Squirrel monkeys may be more numerous than people in French Guiana. The French overseas territory is about the size of South Carolina yet harbors fewer than 200,000 people—only about two and a half for every square kilometer, according to UN averages.
But French Guiana is "mostly tropical forests," the UN's Gerland said. "And there are still some native peoples living in remote locations. It's not easy to improve infrastructure in Guiana, because of this landscape."
The desert is reclaiming buildings in Kolmanskop, a Namibian ghost town that was once home to a working diamond mine. (See more Namibia pictures.)
Namibia is about the size of Texas and Louisiana combined and home to about 2.1 million people, but vast stretches of its arid landscape are extremely uncrowded.
"Namibia is primarily a desert country, and like many of those on this list, it has its environmental challenges," the UN's Gerland said.
Still, the country features an enlightened approach to natural resources and was the first in the world to mandate environmental protection in its constitution, the Center for Sustainable Destinations' Tourtellot said. "They have an excellent reputation in terms of sustainable tourism, or ecotourism, and cultural tourism"—with an emphasis on adventure, including safaris and indigenous experiences.
Cradle Mountain-Lake St. Clair National Park in Tasmania is one of many Australian areas well-protected from human pressures. (See your Australia pictures.)
Australia is almost the size of the U.S.'s lower 48 states, and there's certainly no shortage of people living in the country—almost 22 million to be exact. But most Australians live in the coastal communities that ring a massive and relatively empty interior.
"If you look at Australia in terms of where people are living, it's basically concentrated where you have water. And there just isn't as much of that resource available inland," the UN's Gerland said.
Still, the outback does offer outsized opportunities for tourists, the Center for Sustainable Destinations' Tourtellot said. "There're the sheep stations, the ranching culture, the desert ecology, and the aboriginal culture as well—which is getting much more involved in tourism."
(Also see "New Australia Mining Boom Taking Toll on Outback Life.")
Photograph by Amy Toensing, National Geographic
With no ice in sight, swimmers enjoy the Mývatn Nature Baths, warmed by Iceland's vast volcanic underground. The island country is about the size of Kentucky but home to roughly 300,000 people-in part because glaciers cover more land here than in all of mainland Europe.
Iceland is home to a relatively homogenous population with few significant recent migrations, the UN's Gerland said. "In recent decades it has also stood out in Europe as one of the places where people live to a very old age"—echoing a global trend toward graying populations, according to the UN.
Population densities here are only about three people per square kilometer, according to UN stats, but the Center for Sustainable Destinations' Tourtellot said the beautiful summer season is a bit busier. (Find out why Iceland is among Traveler magazine's top 20 destinations for 2012.)
"The center of Iceland is uninhabited, but in the summer you'll see a lot of hikers and people driving on four-wheel-drive tracks. A lot of Europeans enjoy adventure tourism in Iceland during the summer," he said. "It's a very wild and interesting place."
Along a creek in South America's Suriname, otters have stripped the vegetation from this site to mark their territory—and humans are unlikely to trespass.
Giant otters are just part of the wild diversity of plants and animals found in the uninhabited tropical rain forest that covers most of this former Dutch colony, which is about the size of the U.S. state of Georgia and home to fewer than half a million people.
Suriname is trying to leverage its vast natural advantages for a growing rain forest ecotourism sector, Tourtellot said. But those same resources also fuel industries such as logging and mining in the interior.
"As you often find in rain forest areas, ecotourism versus deforestation has become a part of the dynamic," he said.
Camels compete for a meal at a former oasis—now overtaken by desert—in Mauritania. Also eager for water, most of the country's 3.2 million people live in cities or along the Senegal River, though there is a population of traditional desert nomads, said the UN's Gerland.
"Because of the environmental challenges many sparsely inhabited places have faced over the centuries, life was very, very tough until a generation or so ago," he added. "And it's still not easy in many of them, although there have been some modern improvements in terms of nutrition, health, and better access to resources."
Mauritania's tourist sites—including enormous sand seas, ancient cities, and empty coastlines—have taken a major hit in recent years due to safety concerns in the wake of terrorist attacks on travelers.