The Fascinating Depths Of The World's Deepest Lakes

Was geology one of your favorite subjects in school? Have you ever wondered if life can exist, and maybe even thrive, thousands of feet beneath the water's surface? If so, then you are in luck. We rounded up some of the world's deepest lakes to showcase how different geological processes and climates have produced unique ecosystems usually hidden from the human eye. Each lake is a treasure, not only to those who appreciate natural beauty but also to scientists studying evolution and extreme environments.

Some lakes have been more thoroughly researched than their counterparts, so in curating this article, we have done our best to use the most reliable sources possible. Each lake is ranked by maximum, not mean, depth. We have also noted situations where traveling to a specific country to see the water body is discouraged due to safety concerns. Nevertheless, we trust that you can still marvel at those lakes' magnificent qualities from the comfort of your home.

Nestled in the Indonesian province of South Sulawesi, Lake Matano is estimated to be anywhere from 1 to 4 million years old. It stretches 17 miles in length and 5 miles in width and hosts an incredibly diverse ecosystem. Its wildlife ranges from the photosynthesizing green sulfur bacteria to a plethora of endemic fish, mollusks, crabs, and shrimp. As you visit, remember that these wildlife urgently need protection. Non-native species threaten to disrupt the ecosystem's balance, as does deforestation and pollution from nickel mining. 

It is no secret that Indonesia is home to some of the world's best snorkeling sites. Lake Matano is no exception and is famous for its clear waters. Though admittedly difficult to access, once there, you can snorkel or dive in the lake, as well as canoe, water ski, and cruise on its surface. You might even find artifacts like pottery and metal tools strewn across the bottom of the lake. Lake Matano's maximum depth is about 1,936 feet. Deep beneath the surface, the water is anoxic, meaning it lacks oxygen. It is also high in iron and devoid of sulfates, just like the Earth's oceans were during the Archean Eon. That is one reason scientific studies are often conducted on Lake Matano.

Note that some parts of Indonesia may be more at risk of terrorism and natural disasters. As such, the U.S. Department of State has issued a Level 2 Exercise Increased Caution advisory for the country. If you decide to travel, take all necessary precautions, such as joining the Smart Traveler Enrollment Program (STEP), to receive assistance during an emergency.

Crater Lake is located in southern Oregon among the Cascade Mountains. It is so magnificent that an entire national park has been created around it. The lake was formed approximately 7,700 years ago when a volcanic eruption shook a mountain so violently that it collapsed on itself. Since then, rain and snowmelt have filled the crater, resulting in a remarkably clean and pure body of water. Subsequent eruptions created Wizard Island, a small mass of land within the lake. 

Crater Lake is one of the best lakes for swimming on the West Coast and a wonderful place to fish. However, SCUBA diving and snorkeling are prohibited to protect the delicate ecosystem. Because of its large size, the surface of Crater Lake rarely freezes, meaning you can admire its deep blue waters year-round. With a maximum known depth of 1,943 feet, Crater Lake is an ecological marvel.

Along the shoreline, you will find crayfish and Mazama newts (an endemic species). If permitted to dive beneath the lake's surface, you might find iron-oxidizing bacteria that can survive in the dark, rock spires and chimneys, and spurts of warm hydrothermal fluids. You would almost certainly see schools of rainbow trout or salmon — both are nonnative fish introduced to the lake between 1886 and 1941. Worms, insects, phytoplankton, and zooplankton also call Crater Lake home. One of the lake's most interesting features, though, is the abundant moss that grows deep beneath the surface and the peat deposits that have accumulated as a result.

Located in the Northwest Territories of Canada, close to where the province borders Alberta, Canada's Great Slave Lake is nothing short of massive. With a length of around 300 miles and a maximum width of about 140 miles, it is North America's fifth-largest lake. The freshwater lake is not a closed system but, rather, a notable supplier of water to the Mackenzie River. 

Great Slave Lake is believed to have a maximum depth of about 2,020 feet. It is home to a large amount of fish, with whitefish and trout being particularly numerous. Indeed, fishing is critical to the local economy and culture. Zooplankton and invertebrate bugs are also crucial components of the local ecosystem. The wildlife in Great Slave Lake is under-researched, but efforts are ongoing to better understand and preserve the fascinating species beneath its surface.

Visitors should not expect to sunbathe and swim in Great Slave Lake. It is extremely cold and frozen for about eight months each year. However, you can still enjoy the water body by dogsledding across its surface during the winter and birdwatching and fishing during the summer. You might plan a visit to Thaidene Nëné National Park Reserve, one of Canada's newest national parks, to see Great Slave Lake. The park encompasses the lake's northeastern corner. Be respectful and mindful of your role as a tourist when visiting. The lake, which is somewhat remote, is named after the Slavey North American Indians (also known as Dene People), and much of the local population remains American Indian to this day.

The northeastern region of the Kyrgyz Republic is dominated by Lake Issyk-Kul, which stretches nearly 111 miles in length and up to about 42 miles in width. It does not directly connect to any other water bodies. Issyk-Kul means "hot lake" in English. While water temperatures peak at only about 68 degrees Fahrenheit during the summer, this lake has the distinguishing characteristic of not freezing during the winter, unlike many others in the region. That's because Lake Issyk-Kul is slightly saline, and saltwater freezes at a lower temperature than freshwater. 

The 25-million-year-old lake is one of the major draws for tourists visiting the Kyrgyz Republic. It is the center of recreational activities, perfect for lounging on the beach, swimming, receiving spa treatments, birdwatching, and hiking in the surrounding mountains. The area has been protected since 1948 and is now on the Ramsar list and among the UNESCO World Network of Biosphere Reserves.

A series of tectonic shifts formed Lake Issyk-Kul, and its maximum depth is an astonishing 2,192 feet. In its depths, you'll find a variety of wildlife, including at least 28 species of fish. The thousands of migratory birds that visit the lake each year can count on a fishy feast. Introduced and endemic species are present; most are in the lake's shallower regions. One of the most famous endemic fish species is the Issyk-Kul chebachok. It is accompanied by other species like whitefish, bream, and rainbow trout.

Although it is known as Lake Malawi in Malawi, it is called Lake Nyasa in Tanzania and Lake Niassa in Mozambique. A volcanic activity approximately 2 million years ago created this freshwater lake. It reaches depths of up to 2,316 feet. It connects to multiple rivers and has dry and wet seasons. Climate change and environmental degradation are major concerns for the surrounding communities, which currently do not have the resources to combat and recover from natural disasters effectively. Responsible tourism can help support the area; indeed, Lake Malawi is one of the best destinations for kayaking around the world.

Lake Malawi National Park was honored as a UNESCO World Heritage site in 1984 for its stunning beauty, impressive biodiversity, and hundreds of endemic fish species that provide unique insights into the inner workings of evolution. Three hundred and forty-five species of endemic cichlid fish, or mbuna as they are known locally, can be found in Lake Malawi. These fish have been compared to Darwin's finches for their role in scientific inquiry. Plenty of other types of fish, including sardines, can additionally be found beneath the lake's surface. Over 100,000 tons of fish are extracted from the lake annually.

You might want to pack your bags to see this lake in person. But note that the U.S. Department of State has issued a Level 3 Reconsider Travel advisory for Mozambique. A Level 2 Exercise Increased Caution advisory is in place for Tanzania and Malawi.

Referred to as Lago O'Higgins in Chile and Lago San Martín in Argentina, this turquoise lake is a must-see for anyone visiting Patagonia. Tourists often take boats on Lago O'Higgins to get closer to its glaciers, where the cracking and splashing sounds of ice calving into the water can be heard. The O'Higgins Glacier is marvelous due to its size — it ranks as the fourth largest Patagonian glacier.

We would argue that Lago O'Higgins is a significant natural feature in itself and worth a few moments of your attention. For starters, with a maximum depth of around 2,742 feet, Lago O'Higgins is one of the deepest lakes in the world. It is also large, sprawling across 391 square miles of remote wilderness. However, it does not possess the royal blue hue you might expect of a deep lake. Instead, it is tinted with turquoise, a result of sunlight refracting off glacial rock particles. 

This remarkably pure water is home to fish like perch, trout, and salmon. You can leisure around Lago O'Higgins by taking one of the aforementioned boat tours or hiking one of its gorgeous, rugged trails. Plenty of activities are supported within Bernardo O'Higgins National Park, and you can find convenient lodging in the nearby Villa O'Higgins.

Of all the lakes on this list, Lake Vostok is the one you are least likely to visit. That's because it is located 2.5 miles beneath Antarctic ice and, therefore, classified as a subglacial lake. Ironically, this lake lies beneath one of the coldest places on Earth. How is such a natural phenomenon possible? Heat deep within the earth prevents the water here from freezing. Nutrients, potentially life-supporting ones, may also seep from the bedrock below.

Nobody has ever seen Lake Vostok with their naked eye, but seismic and radar technology has been able to detect and analyze this unique body of water. Research indicates that it is likely composed of freshwater and probably home to organisms found nowhere else on the planet. Advanced technology has estimated that Lake Vostok is over 150 miles long and up to 31 miles wide. Not to mention, it has a maximum depth of approximately 2,953 feet. 

Lake Vostok's age and whether it was formed by volcanic activity is heavily debated. Some research has suggested that sedimentary rock lies beneath the lake. Other evidence also proposes that Lake Vostok formed in a rift valley. Ice cores can be used to learn more about the lake, though scientific inquiry is limited due to the extreme natural environment.

Los Glaciares National Park is home to a few incredible freshwater lakes, including Lago Argentino and Lago Viedma. The latter ranks as one of the deepest lakes in the world, and though estimates are scarce and vary widely, some think it has a maximum depth of 2,953 feet. Lago Viedma is more difficult to access than Lago Argentino, but your efforts will be rewarded with fewer crowds. You can visit the lake by hiking around the Fitz Roy Group or trotting on a horse.

Because Lago Viedma is fed directly by the Viedma Glacier and there are fewer fjords to filter its sediment-rich water, this Argentine lake is colored with more of a gray hue than nearby Lago Argentino and Lago San Martin, which are both decidedly turquoise. Even so, you could spend hours admiring it, perhaps while casting a line to reel in fish like rainbow trout, lake trout, and brown trout. The shores of Lago Viedma are an excellent place to birdwatch, too, and you might catch sight of some endangered species. We can't promise any sightings of calimayos, though, as these mystical horses hail from local folklore.

Look at a map, and you'll find that the Caspian Sea is indeed a lake. It is bordered by five countries: Kazakhstan, Turkmenistan, Azerbaijan, Russia, and Iran. The first two countries are the safest to visit, as the U.S. Department of State has issued warnings for the latter three.

The Caspian Sea is the world's largest saltwater lake and third deepest lake. Specifically, it spans roughly 149,200 square miles, and its maximum known depth is an astounding 3,360 feet. The surface of the lake itself is 90 feet below sea level, so we mean it when we say this lake is deep. Beneath all that water lies sedimentary rock and evidence of what used to be river valleys thousands of years ago. The oldest part of the lake is estimated to be at least 541 million years old.

When it comes to marine life, the Caspian Sea is a precious reservoir of endemic species. One of the most prominent is the Caspian seal, an adorable creature that can reach up to 50 years old in their natural habitat. Other animals include crabs, clams, algae, and fish like herring, sprat, and perch. Sturgeon in the lake are prized for their caviar. All told, approximately 850 animal species and over 500 plant species call the Caspian Sea home. These wildlife need protection: Overfishing and the oil and gas industries are a major concern for the lake's biodiversity.

You can visit one of four countries in Africa's Great Rift Valley to see Lake Tanganyika: Tanzania, the Democratic Republic of the Congo, Burundi, or Zambia. Of these countries, Zambia is currently the safest to visit, followed by Tanzania. The U.S. Department of State has issued a Level 4 Do Not Travel advisory for the Democratic Republic of the Congo and a Level 3 Reconsider Travel advisory for Burundi.

Lake Tanganyika is an astonishing 410 miles in length and 4,710 feet in depth. It is a freshwater lake with steep shorelines that are a testament to the lake's geological history: The Great Rift Valley was formed by the stretching of tectonic plates, which often results in cliff formation. Geologists estimate that Lake Tanganyika is roughly 20 million years old.

Rice, sugarcane, maize, coffee, and oil palms thrive along the lake's coast. Meanwhile, hippopotamuses, crocodiles, crabs, more than 350 species of fish, and 171 bird species can be found delighting in its waters. Over 2,000 species live in the lake, and between 500 and 600 are endemic. Such species live in the upper layers of the lake since the deepest parts are anoxic and, due to lack of circulation, have been undisturbed for millions of years. The wildlife here is threatened by urbanization, nearby deforestation, and intensive agricultural practices. Consider an eco-friendly visit to Tanzania's Mahale Mountains National Park, a hotspot for chimpanzees. Indeed, the Mahale rainforest is one of the most spectacular rainforests in the world.

Lake Baikal is a remote freshwater lake in southern Siberia with many accolades. Yes, it is considered the deepest lake in the world, with a maximum known depth of 5,315 feet. But it is also the oldest lake in the world, believed to have formed 20 to 25 million years ago. Lake Baikal's estimated 5,500 cubic miles of water constitute roughly 20% of Earth's total unfrozen freshwater. Because of its remote and pristine nature, the lake and many surrounding mountains were deemed a UNESCO World Heritage site in 1996.

Lake Baikal does not disappoint when it comes to biodiversity, either. An impressive number of endemic species flourish in its waters, including over 1,500 animal species and hundreds of plant species. Fifty or so species of fish live in Lake Baikal, notably the omul salmon, sturgeon, golomyanka, whitefish, and grayling. The lake's surface can freeze for up to six months each year, so wildlife must be adapted to cold temperatures. For instance, the Baikal seal uses its claws to cut holes in the ice before diving as far as 1,300 feet below the surface to feed. 

The lake's incredible ice formations are also beautiful to behold, making Lake Baikal one of the world's strangest natural wonders. It is important to note that U.S. citizens are not advised to travel to Russia. The Department of State has issued the country a Level 4 Do Not Travel warning.