There is something romantic about traveling by highway. In the age of high fuel prices and low-cost airlines, it is often faster and cheaper to travel by air. But the idea of traveling in a landscape, rather than above it, is still very alluring.

And when you are on the road, you have infinitely higher odds of encountering adventure. Some of the world's most scenic, most far-flung, and loneliest highways provide experiences, sights and challenges that can make for an epic road trip.

Here are nine highways with extreme conditions, amazing scenery, and a strong chance for unforgettable adventure.

U.S. Route 50, Nevada portion

U.S. Highway 50, Loneliest Highway in the World

Photo: Ron Reiring/Wikimedia Commons

Famously dubbed the “Loneliest Highway in the U.S.” by Life magazine, Nevada's portion of U.S. Highway 50 is almost the polar opposite of the state's most famous road, Las Vegas Boulevard South (the Las Vegas Strip). Since it was first named “the Loneliest Highway” in the mid-1980s, it has become popular with intrepid road-trippers, stripping some of its off-the-radar allure. Nonetheless, Highway 50 remains a largely remote road, traveling across deserts, through mountain ranges, and even past ghost towns. Carson City, Lake Tahoe and the Great Basin National Park all sit along U.S. 50, which actually starts in Sacramento, Calif., and continues through Nevada, across the Plains states and all the way to Ocean City, Md.

Trans-Canada Highway

With a main route that spans nearly 5,000 miles, this is one of the longest national highways in the world. The Trans-Canada runs from Victoria, British Colombia, all the way to the edge of Newfoundland in Canada's far east. The attraction of road-tripping on this highway is obvious: It passes through all of Canada's most beautiful landscapes. Drivers can see the lush forests of British Colombia, the picturesque Canadian Rockies and the beautifully austere plains before driving through the forests and lakelands of the eastern half of the country.

Karakoram Highway, China and Pakistan

Karakoram Highway

Photo: Dmitry P/Flickr

Though it is not the highest public road in the world, the Karakoram Highway, which runs between Pakistan and China, holds the distinction of being the highest major thoroughfare and the highest international highway on Earth. It passes through its namesake mountain range and reaches an elevation of more than 15,000 feet at its highest point. The whole highway stretches for about 800 miles from Kashgar, a city in western China, to Abbottabad, on Pakistan's side of the Kashmir Region. There is some beautiful mountain scenery along the road, but harsh alpine conditions, high altitude, landslides and unpredictable traffic will make any trip on the Karakoram much more than a leisurely sightseeing drive. The route is a favorite of adventure tourists, who stop off to climb the region's mountains and explore its valleys along the way.

Trans-Siberian Highway

Less famous than the Trans-Siberian Railway, this network of highways crosses Russia's vast interior and vies for the title of the world's longest highway. In all, it stretches for about 6,800 miles from St. Petersburg in the east to Vladivostok in the far west. Some sections of the road are very modern and can be traveled easily, though poor weather is always a concern during the winter. Until recently, some eastern parts of the highway were no more than dirt tracks that became flooded and muddy during rains, stranding drivers and making them vulnerable to Siberia's “road pirates.” Recent paving projects have made the road more passable and much safer.

Highway 1, Australia

Highway 1, Australia

Photo: Tony Bowden/Flickr

Australia's Highway 1 is the longest highway in the world. It is a “ring road” that circles the entire continent, mainly running along the coast. Highway 1 is a great road trip route because of the diverse landscapes and the fact that you can visit all of Australia's main cities along the way. If you make the complete 360-degree trip (from Point A all the way around back to Point A), you will drive on modern multi-lane highways through major urban areas some of the time. In very rural areas, the highway is no more than a paved two-lane road. In a few areas, it is even less than that. The drive will certainly be a challenge for anyone who undertakes the complete circuit, but getting to see all of Australia (aside from its vast interior) will certainly make it worthwhile.

Tarim Desert Highway, China

China's Tarim Desert Highway is 342 miles long. 277 of those miles run through an uninhabited landscape dominated by the 20-foot sand dunes that characterize the large but little-known Taklamakan Desert in far western China. The stark landscapes and almost complete absence of habitation make this a great get-away-from-it-all road. A single “oasis” with a gas station and restaurant sits at the halfway point of the highway. But sand isn't the only type of scenery on this journey. Shrubs planted along the sides of the highway aim to prevent the dunes from shifting and covering the pavement. The result is a 250-foot-wide “greenbelt” running along nearly four-fifths of the highway.

Dalton Highway, Alaska

Dalton Highway, Alaska

Photo: Terry Feuerborn/Flickr

The Dalton Highway is a 414-mile road that stretches from Livengood, a village north of Fairbanks, Alaska, all the way up to the oil town of Deadhorse, not far from the Arctic Ocean. Aside from its starting and ending points and pump stations along the way, drivers pass only two towns while on this road, and both have populations of less than 30. The Dalton is rough and primitive in places, there is no cellphone service, and driving with survival gear is strongly encouraged. Anything less than a four-wheel drive vehicle is inadvisable at best. Most of the traffic on this road comes from trucks supplying the oil fields in and around Deadhorse. Those who choose to make the journey are in for some amazing scenic treats. The Gates of the Arctic National Park and the Arctic National Wildlife Refuge are located near the highway, and there are endless stretches of tundra, pine forests and mountain ranges to enjoy along the way.

Trans-African Highway 4, Cairo to Cape Town

This ambitious project is not yet complete as of this writing, although it is possible to travel along the proposed route. When it is completed, Highway 4 will stretch for more than 6,300 miles. Desert, mountain, valley and savanna landscapes are all on offer to adventurous souls who want to drive the already completed sections of this route. However, political instability and conflict, along with poor road conditions in some areas, make it a tough journey. Other transcontinental projects, such as a highway from Mombassa, Kenya, to Lagos, Nigeria, will also be completed in the near future.

Iceland Route 1

At 832 miles, this ring road around the island nation of Iceland is certainly not the longest route on our list. It does, however, have some of the most unusual roadside scenery. Glaciers, mountains, active volcanoes, steaming lakes, and waterfalls make it exciting to look out the windshield. Since the road passes many of Iceland's most famous sights, it is popular with tourists, and locals also like to circle the country during the summertime. At any time of year, the sections of road that are the farthest away from civilization, such as those along the southeastern coastline, see only a few cars per hour on average. Feeder roads provide even greater access to scenery. For example, the road through the mountain pass between the highway and the fjord-lands town of Seydisfjordur offers scenery so breathtaking that it earned a role in a major film, "The Secret Life of Walter Mitty."

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