View of Laguna Colorada in the Bolivian Altiplano.

In simple terms, a lake is a body of water that is landlocked. Millions of lakes dot the planet, and they exist in nearly every environment, from the polar regions, to the rainforests and even the driest deserts. Everywhere lakes are found, they function as important parts of the ecosystem and allow other life to flourish. 

Some lakes are the lasting result of catastrophic events like meteor strikes or volcanic eruptions, while others have formed due to glacial movement or geological processes that span millennia. There are clear, blue lakes that are among the world's purest sources of water, and others that are many times saltier than seawater. Some lakes, containing noxious gases or boiling water, are dangerous to humans.

The following lakes rank amongst the most bizarre in the world.

1

of 13

Laguna Colorada

Laguna Colorada is a salt lake in southwestern Bolivia with distinctive orange-red water. It doesn't even look real. Though the lake is about six miles wide today, ancient shorelines show that the lake was once much larger in size. Its unique color comes from red algae that grows in the water. Occasionally, the water will turn green instead, when a different type of algae grows more prominent due to changes in the water's temperature and salt content. The lake is a breeding ground for large populations of James's flamingos, which feed on the algae. Islands of bright white borax deposits dot the lake, a byproduct of saltwater evaporation.

2

of 13

Boiling Lake

Dominica's Boiling Lake is one of the largest hot lakes in the world, measuring over 200 feet across and at least 35 feet deep. Though the water has been measured to be 180-197 degrees F (below the boiling point of 212 degrees), it appears to boil due to volcanic gases that bubble in the water. In geological terms, the lake is above a fumarole, or a crack in the Earth's crust, that releases gases and heats the water. Thanks to its heat, the lake is usually surrounded by clouds of steam and fog. 

3

of 13

Plitvice Lakes

Looking like they emerged from a fairytale, the Plitvice Lakes are a series of 16 turquoise-blue lakes in central Croatia, connected by waterfalls and caves. Each lake is separated from the others by thin, natural dams of travertine, an unusual form of limestone deposited over time by mineral-rich water. The fragile travertine dams grow at a rate of one-half inch a year. The lakes, set in the forested landscape of the Dinaric Alps, are the central attraction of the Plitvice Lakes National Park. 

4

of 13

Lake Nyos

Cameroon's Nyos Lake is one of the world's only known exploding lakes. Yes, you heard that right, an exploding lake. The lake sits on the side of an inactive volcano and above a pocket of magma that leaks carbon monoxide into the lake. Scientists believe that seismic activity and volcanic eruptions can agitate the water, causing the carbon monoxide to exit the lake in a cloud of gas known as a limnic eruption. 

In 1986, the lake burped a massive plume of carbon dioxide, suffocating all living things in a 15-mile radius, including 1,746 people and about 3,500 animals. It was the first large-scale asphyxiation event ever recorded as a result of a natural disaster. The lake has since refilled with carbon dioxide, and researchers believe a similar eruption could happen again.

5

of 13

Aral Sea

Once the fourth largest lake in the world, the Aral Sea has largely transformed into an arid desert after shrinking in size for decades. About 90% of the lake, which sits on the border of Kazakhstan and Uzbekistan, has dried up entirely. Water from the rivers that sustained the lake was diverted to Soviet-era irrigation projects beginning in the 1960s. 

The Aral Sea's shrinkage led to ecosystem collapse and widespread pollution. The lake water that remained became 10 times saltier, and most fish and other wildlife disappeared. 

In 2005, the Kazakh government completed an eight-mile dam that prevented the North Aral Sea, the largest of the remaining lakes, from draining into the dry basin that was once the main body of the lake. Since then, the water level in the North Aral Sea has increased, salinity has decreased, and fish populations have rebounded.

6

of 13

Pitch Lake

This lake is a great choice for a lake not to take a swim in. Trinidad's Pitch Lake is a pool of hot, liquid asphalt and the largest natural deposit of asphalt in the world. The lake covers more than 200 acres, reaches 250 feet deep, and harbors alien-like organisms that can withstand its unique chemical makeup.

Though the lake hasn't been studied extensively, researchers believe the asphalt is the result of oil that seeps into the lake from a deep fault line in the Earth's crust. Scientists have found that novel microbial life can thrive in Pitch Lake and believe that this discovery provides some evidence that the hydrocarbon lakes on Saturn's largest moon, Titan, could also support life.

7

of 13

Don Juan Pond

Don Juan Pond is a small lake in Antarctica that is so salty it does not freeze even when temperatures drop far below zero. With a salinity level of over 40%, it is one of the saltiest bodies of water in the world and more than 10 times saltier than ocean water. The salt in Don Juan Pond is 95% calcium chloride, which lowers the water's freezing point more than other salts would, and Don Juan Pond has been observed to remain liquid at -58 degrees F. While scientists do not fully understand how the lake exists in the dry conditions of Antarctica, studies show that it is likely fed by water from a deep underground source.

8

of 13

Dead Sea

The Dead Sea is one of the largest and deepest hypersaline lakes in the world. Though it stretches for 31 miles along the border of Israel and Jordan, the lake supports no animal or plant life except for some salt-loving microorganisms. The salt content of the Dead Sea also increases the density of the water, and people swimming here float more easily than in other bodies of water. 

Its shores are also the lowest point on land in the world, with the surface of the lake about 1,420 feet below sea level. In addition, the shores get lower every year—since 2010, the surface level of the lake has been dropping by about three feet every year. 

9

of 13

Klikuk

In winter and spring, Klikuk (also known as Spotted Lake) looks much the same as any other small mountain lake in British Columbia, Canada. But in summer, when soaring temperatures cause the water to start evaporating, the lake bed transforms, revealing yellow, green, and blue pools of mineral-rich water. The pools of water vary in color according to precipitation levels and which minerals—like calcium, sodium sulfate, and Epsom salt—are present in each pool.

The Syilx, a First Nations people who traditionally lived in British Columbia's Okanagan Valley, used Klikuk for centuries as a sacred site with therapeutic waters and minerals. In 2001, the Syilx purchased the land around the lake, which guaranteed its protection as a historical and cultural landmark.

10

of 13

Lake Balkhash

Here is a lake with an identity crisis. Kazakhstan's Lake Balkhash earns the rare distinction of being both a freshwater and saltwater lake. Its western half, which is wide, shallow, and milky green in color, mostly contains freshwater. Its eastern half, which is narrower, deeper, and dark blue, is much saltier. 

This strange characteristic can be explained by the lake's sources of water. Its main water source, the Ili River, drains into the lake on its southwestern side, creating a constant flow from west to east. But the lake has no outflow, and as water collects and evaporates on the eastern side, it becomes more saline.

Hydroelectric dams and irrigation projects have diverted some of the water from the Ili River, and some studies warn that these diversions could cause an environmental disaster akin to the Aral Sea in the future.

11

of 13

Tonlé Sap

The unique ecosystem of Cambodia's Tonlé Sap evades classification as either a lake or a river. During the dry season, the waters of the Tonlé Sap drain peacefully into the Mekong River, and then the South China Sea. But during the monsoon season, the flow of water is so massive that the Mekong River is completely inundated, forcing the Tonlé Sap to flood, swell into a lake, and reverse flow away from the ocean. The seasonal flooding creates a wetland environment of amazing diversity and one of the world's most productive natural fisheries.

12

of 13

Crater Lake

Oregon's Crater Lake is exactly what its name suggests—a water-filled crater left over from an ancient volcanic eruption. When Mount Mazama violently erupted 7,700 years ago, it created a massive caldera running nearly 2,000 feet deep through the heart of the mountain. Since then, rain and snow have filled the crater, forming the deepest lake in the United States with some of the clearest water in the world. Crater Lake receives about 43 feet of snow every year, and precipitation rates are double that of evaporation. Scientists believe that the crater doesn't overflow because water seeps into the ground at a rate of about two million gallons an hour. 

13

of 13

Lake Baikal

At 25-30 million years old and 5,387 feet deep, Lake Baikal is the world's oldest and deepest lake. Though this lake in southern Siberia is not the world's largest freshwater lake by surface area, it is easily the most voluminous. By itself, Lake Baikal contains about 20% of the world's unfrozen freshwater. The lake is situated over the Baikal Rift Zone, the deepest continental rift on Earth, and the area is subject to frequent earthquakes.

The Lake Baikal ecosystem supports more than 2,000 plant and animal species, two-thirds of which are found nowhere else on the planet. Due to its geological and ecological importance, the region was declared a UNESCO World Heritage Site in 1996.