There were over 2 million visitors to Iceland in 2017, according to the Reykjavík Grapevine. That's more than six times the number of people who currently live on the island. The country's tourism industry is booming and doesn't show any signs of slowing down. One of the biggest draws for visitors is the incredible landscape of the island. Iceland is unlike any other country in the world. In fact, sometimes Iceland makes you feel like you are on another planet entirely. Here are four of the most out-of-this-world places to visit in the Land of Fire and Ice.

Mount Mælifell

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Mount Mælifell provides the perfect backdrop for an otherworldly adventure. The mountain itself is an active volcano, covered in vibrant green moss that changes color throughout the year. The setting around the volcano is even stranger, though. The green mountain juts up from a field of black sand, which was created by the volcano itself. The contrast of the vibrant, lively green color coming out of the middle of all that black sand is really something to see. But you'll need to time (and plan) your visit carefully. You have to reach Mount Mælifell by four-wheel-drive vehicle due to its remote location, but the road out to the area is often flooded. The roads are so rough that it is recommended you only go via a tour or a specially equipped vehicle, according to Iceland Review. Your best bet, says travel site Hit Iceland, is to visit from mid-Summer through October when the roads are at their clearest.

Reynisfjara Beach, Vík

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This is another area known for its black sand. But Reynisfjara Beach adds another dimension to its out-of-this-world landscape. Look beyond the stunning black sand beach, and you'll see the basalt cliffs jutting up along the beach and rock stacks coming out of the water. The basalt cliffs look like perfectly carved cubes of stone stacked on top of each other. Their unique formation makes them look like a stone staircase leading to nowhere.

The stone stacks out in the water are just as amazing. According to Guide to Iceland, local folklore says these stacks were once living trolls. The trolls were out in the water trying to capture passing ships when the sun came up and froze them in place for the rest of time. The story surrounding the area definitely adds to the other-planet atmosphere of this incredible beach. IMDB notes that the beach was also a filming location for the 2017 Star Wars film Rogue One.

Víti Lake, Askja

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Located in the highlands of Iceland, the Askja caldera is an area that isn't often visited by tourists. That's because it's off of the famous ring road and difficult to access. Like Mount Mælifell, you'll need to either rent a specially equipped four-wheel-drive vehicle or book a tour to get to this location. But the extra effort is worth it. A caldera is a crater formed by a volcano. According to Guide to Iceland, the Askja caldera formed in 1875. At that time, a volcanic explosion in the area altered the landscape forever. Not only did the eruption form new calderas in the area, but it also covered the surrounding land in a fine, powdery volcanic ash. This ash is yellow, making the entire area seem completely surreal.

Even more alien, though, is Víti Lake. The lake formed when water seeped into the depression of the caldera. Víti Lake is warm enough to swim in, reaching temperatures around 77 degrees Fahrenheit. Warmed by the volcanic activity below, the sulfury water creates a natural hot spring. So while it's not exactly toasty warm, it's definitely warm enough to get in and enjoy. The color of the water is pretty unusual, too. It is a murky opaque blue and can change depending on how much rain the region has had recently. Between the yellow landscape, opaque blue waters, and the experience of swimming in a crater made from a volcanic explosion, you'll definitely feel like you are on another planet.

Ice Caves of Vatnajökull

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Vatnajökull is a glacier that sits in one of Iceland's national parks. According to Iceland Monitor, it became a World Heritage Site in 2019. The park itself is massive, taking up about 14% of Iceland itself. Because of the huge size, it encompasses a variety of landscapes, each of which could have its own section as an out-of-this-world place to visit. But you'll find one of the most unique locations within the glacier itself. That is, within the ice caves that form there during the coldest parts of winter.

Visitors could return to the ice caves of Vatnajökull year after year and never see the same caves twice. That makes this place feel even more out-of-this-world. Visit Vatnajökull writes that new caves form every year after last year's caves melt away. Some of the caves are vast, too, creating an under-glacier tunnel system that allows melting ice to flow back out to the sea. Scouts go out to find the largest, safest caves to bring visitors to during the winter months. They find the most interesting caves to wow their tour groups, and these incredible formations rarely disappoint.

The ice caves are far more than simple caverns in the ice, and each one is different. Some have walls of rippling ice that looks like frozen waves. Others form ice that's so pure it's luminescent, glowing softly with blue light. You'll feel like an explorer on a distant icy planet as you take in the crystal clear ice that plays with the light around you.

And while they are beautiful, they are also incredibly dangerous. Visitors should only visit the ice caves with an experienced tour guide who can provide the right safety equipment for the journey.