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Sunken forest of Lake Kaindy, Kazakhstan -

Lake Kaindy contains dozens of trunks of submerged spruce trees to create a sunken forest. The upper parts of the protruding tress resemble needles.

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Richat Structure, Mauritania -

A prominent circular feature found in the Sahara Desert known as the Richat Structure is an eroded geological dome, 40 km (25 mi) in diameter. Locals call it the "Eye of the Sahara."

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Salar de Uyuni, Bolivia -

One of the most extreme and beguiling landscapes on the planet, the Salar de Uyuni is the world's largest salt flat, left behind by prehistoric lakes evaporated long ago.

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Moeraki boulders, New Zealand -

Appearing like a wayward set of ogre's marbles, the Moeraki boulders lying along a stretch of Koekohe Beach between Moeraki and Hampden are distinguished for their unusually large and spherical shape. Erosion by wind and the wave action of mudstone is the likely cause.

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Caño Cristales, Colombia -

There's a river in Colombia called Caño Cristales that's commonly referred to as the "River of Five Colors" or the "Liquid Rainbow" for its extraordinary array of tints and hues. The bed of the river from the end of July through November is variously colored yellow, green, blue, black, and especially red, a transformation considered one of Mother Nature's crowning glories. The vivid canvas is produced during the reproductive process of the aquatic plants in the river.

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Blood Falls, Antarctica -

Located in Antarctica's remote McMurdo Dry Valleys, this odd-looking blood-red waterfall is the result of an outflow of an iron oxide-tainted plume of saltwater, flowing from the tongue of Taylor Glacier. The scene has been captured by the Antarctica National Science Foundation's Peter Rejcek.

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Reed Flute Cave, China -

A natural limestone cavern that has formed over a period of 180 million years or so, Reed Flute cave is named for a variety of naturally abundant reed that grows near the entrance and which is actually used to make the musical instruments. The landmark cave, found near Guilin in China's Guangxi region, is a popular tourist attraction.

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Giant's Causeway, Northern Ireland -

Legend says that the 40,000 or so interlocking basalt columns, the tops of which form stepping stones that disappear into the sea, were made by a giant who built a causeway across the North Channel to meet a battle-ready foe in Scotland.

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Eisriesenwelt, Austria -

The Eisriesenwelt, which roughly translated means "World of the Ice Giants," is a natural limestone and ice cave located in Werfen, near Salzburg. It is the largest ice cave in the world.

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Chocolate Hills, Philippines -

So named for their resemblance to bonbon confection, the Chocolate Hills, a geological formation in the Bohol province of the Philippines, number over 1,000 mounds. The green grass turns brown during the dry season, hence their quirky moniker.

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Mono Lake, USA -

California's Mono Lake is famous for its weirdly shaped tufa towers—limestone columns that rise above the surface like extravagant examples of contemporary sculpture.

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Darvaza gas crater, Turkmenistan -

Often referred to as the "Gates of Hell," the Darvaza gas crater was created by accident when the ground under a Soviet drilling rig working a natural gas field gave way. Scientists subsequently set the sinkhole on fire to burn off noxious gases, and 50 years later it's still burning brightly.

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Long and Black Lakes, Portugal -

Lakes Lagoa Comprida and Lagoa Negra ("Long and Black Lakes") on Flores island in the Azores archipelago are two of several volcanic lakes located within the interior of the island. Comprida is noted for its emerald-green surface hue, and Negra for its ink-blue cast.

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Babele, Romania -

Babele is an area on the Bucegi Mountains plateau in Romania where you can find the peculiar mushroom-shaped rock formations created by centuries of erosion and varying hardness of the rock layers.

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Kilauea Volcano, USA -

Hawaii's Big Island vents its fury by spitting out lava from the mouth of Kilauea Volcano and coughing it up, hissing and steaming, into the ocean off the island's southeastern shore.

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Stone Forest, China -

The towering, needle-like limestone towers of the Shilin Stone Forest in China's Yunnan province are believed to be over 270 million years old.

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Well of Barhout, Yemen -

The Well of Barhout, known as the "Well of Hell," is located in the desertof Yemen's Al-Mahra province. The giant hole is 30 m (98 ft) wide and thought to be anywhere between 100 and 250 m (382 and 820 ft) deep. Local folklore says it was created as a prison for demons—a reputation bolstered by the foul odors rising from its depths.

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Tessellated pavement, Australia -

The world's best-known example of a  tessellated pavement is found at Lufra near Eaglehawk Neck on the Tasman Peninsula of Tasmania. This particular geological anomaly is the result of erosion that takes place at low tide when salt crystals create a series of concave depressions in rocks.

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Pamukkale, Turkey -

The landscape around Pamukkale in Denizli province, southwestern Turkey, is blanketed in a carbonate mineral deposited by the flowing of mineral water. The result is a series of shimmering snow-white limestone travertine terraces holding pools of turquoise mineral-rich springs.

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Fingal's Cave, Scotland -

Located on the uninhabited island of Staffa, in the Inner Hebrides of Scotland, Fingal's Cave is formed entirely from hexagonally jointed basalt columns.

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White Desert, Egypt -

The enormous chalk rock formations created over decades through erosion by wind and sand define Egypt's White Desert National Park.

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Devils Tower, USA -

Moviegoers will recognize this extraordinary geological feature from Steven Spielberg's science fiction classic 'Close Encounters of the Third Kind' (1977). The extraterrestrials emerged from their mothership at Devils Tower in Wyoming, a huge butte of igneous rock rearing up over the Black Hills in northeastern Wyoming.

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Skaftafellsjökull glacier, Iceland -

An impressive landmark feature of the Staftafell preservation area, Skaftafellsjökull glacier is a huge tongue of ice sticking out from Iceland's largest ice cap, Vatnajökull.

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Sailing stones, USA -

The mysterious sailing stones of the Racetrack Playa in California's Death Valley appear to move across the valley floor without human or animal intervention. These rolling rocks are in fact lent traction by the effects of floating ice panels and the wind.

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Old Faithful, USA -

The cone geyser in Yellowstone National Park known as Old Faithful is one of America's best-loved geothermal features. Its highly predictable show-stopping performance sees anywhere between 14,000 to 32,000 ltr (3,700 to 8,400 US gal) of boiling water belched to a height of 32 to 56 m (106 to 185 ft) lasting from one to five minutes.

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Marbles Cave, Chile -

One of the most isolated natural treasures in the world, the enchanting Marble Caves are concealed in the heart of Patagonia. Lying in waters shared by Argentina and Chile, the cave walls oscillate between a hazy azure to a rosy pink.

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Lake Hillier, Australia -

Western Australia's saline Lake Hillier achieves its rose-pink hue due to the presence of an organism in the water called Dunaliella salina.

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Spotted Lake, Canada -

One of Canada's strangest and least known bodies of water is Spotted Lake, located northwest of Osoyoos in the eastern Similkameen Valley of British Columbia. It brims with rich concentrations of various minerals, including magnesium sulfate, calcium, and sodium sulfates. During summer, most of the water evaporates to reveal colorful mineral deposits shaped as rings or spots.

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Eternal Flame Falls, USA -

On a quest for the eternal flame? Then head for Shale Creek Preserve, a section of Chestnut Ridge Park in western New York. Tucked away behind a cascading waterfall is a tiny grotto that emits natural gas. When lit, it produces a small flickering flame that's visible nearly year round. And if for any reason it's extinguished, the flame can easily be relit.

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Lake Baikal, Russia -

Arrive at Lake Baikal in southern Siberia mid-winter and marvel at the cracked and bubbled ice that freezes over the water's surface for nearly five months of the year.

Sources: (CNN Travel) (Deutsche Welle) (Salzburg.info) (National Geographic)

See also: The unseen side of famous landmarks

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