Lakes with impressive depths or unique geological features that obscure their true scale are often, misleadingly, labeled as “bottomless lakes”. Despite lakes being found at staggering elevations and being able to produce their own tsunamis, they still lack one feature: an actual bottomless depth.

While no lake can truly claim to be bottomless, some appear impressively close by either plunging to monumental depths or featuring characteristics that create the illusion of being never-ending.

The world’s deepest lakes

The deepest lake on Earth, Lake Baikal, reaches an extraordinary depth of 1,642 meters (5,387 feet). Located in Siberia, Russia, it contains about 20 percent of Earth’s unfrozen freshwater, making it the largest freshwater lake by volume. 

As the world’s oldest known lake, having formed around 25 million years ago, Baikal’s remarkable depth is partly due to the area’s tectonic activity, as it lies at a divergent plate boundary. Nestled in the planet's deepest continental rift, Lake Baikal is fed by over 300 rivers and drained by just one, leaving its unreachable bottom more than a kilometer below sea level.

Another lake that could easily be assumed to be bottomless is Lake Tanganyika, located in Africa, bordering Zambia, Burundi, Tanzania, and the Democratic Republic of the Congo. At a depth of 1,436 meters (4,710 feet), it’s the world’s second-deepest lake – and, stretching 660 kilometers (410 miles), it is also the longest freshwater lake. With its brackish waters, the lake sits at the crossroads of eastern and western African floral regions, supporting a rich diversity of plant and animal life.

Sinkholes and cenotes

Aside from lakes that are just incredibly deep, some of the most convincing bodies of water to appear "bottomless" come in the form of sinkholes or cenotes – which are formed when the top of a cave structure collapses, exposing a large water-filled cavity.

As cenotes form around sometimes vast cave systems, they can look like simple lakes from the surface, but with a deep base that extends to the cavernous space below. Common in the Yucatán Peninsula, cenotes were once used as sites for ritualistic offerings whereby objects, and sometimes humans, were thrown into their apparent never-ending depths.

The Great Blue Hole in the Caribbean Sea is a giant underwater sinkhole that plunges 124 meters (407 feet). Aerial views of the hole show a vast cavern surrounded by shallow ocean waters, this enticing structure and its clear waters make it a popular site for divers.

In the United States, Bottomless Lakes State Park in New Mexico is home to nine sinkholes, ranging from 5.5 to 27 meters (18 to 90 feet) in depth. The lakes’ murky waters may have fuelled the myth of their "bottomless" nature. However, the park’s name reportedly originated from a group of vaqueros – Mexican cowboys – who, in an attempt to measure the depth of the lakes, tied ropes together and dropped them into the water. When the ropes failed to reach the bottom, the lakes were deemed “bottomless”.

While no lake is truly bottomless, some come pretty close with their impressive depths or features that give the illusion of endlessness. These lakes preserve ancient ecosystems and provide valuable insights into Earth's history, proving that, while we may never find a truly bottomless lake, what lies beneath can still be fascinating.