What (and Where) Is the World's Oldest, Deepest, and Largest Lake?

You might be unfamiliar with the oldest, deepest, and largest lake in the world. Located in the heart of Siberia, Lake Baikal is visited by those adventurous enough to embark on a three-day journey aboard the Trans-Siberian Railway from the capital of Moscow.

Narrow in width and crescent-shaped, Lake Baikal isn’t as large as you’d expect, though if it were a country, it would still be bigger than Belgium. But this ancient body of water reaches far deeper than any other lake on the planet and draws well over a million visitors from across the globe every year to its shores. Here’s everything you need to know about this unique body of water.

Ancient Origin

On the shore of Lake Baikal, Russia. Wood engraving, published in 1893.
Credit: ZU_09/ iStock

Lake Baikal formed roughly 25 million years ago from glacial meltwater due to receding ice, and is usually recognized as the world’s oldest lake! Compared to the Great Lakes in North America, which are estimated to be roughly 20,000 years old and didn’t reach their present volumes until about 3,000 years ago, Lake Baikal’s history is incredible.

Scientists believe that Lake Baikal’s lakebed is actually an ancient rift valley. Caused by a divergent plate boundary, the geologic rift likely deepened from erosion and filled with water. According to annual measurements, Lake Baikal is expanding at a rate of roughly 0.8 inches per year. The region surrounding Lake Baikal is seismically active — prone to earthquakes and home to numerous hot springs surrounded by cedar, pine, and larch trees. There’s just one lake on Earth that could potentially top Baikal’s age. Scientists can’t agree on how old Lake Zaysan in Kazakhstan might be, but some archaeologists claim there are paleontological and geological clues in the area that indicate it could date from the late Cretaceous Period and could be 70 million years old! If the evidence stacks up, Lake Baikal will be relegated to second place.

Unparalleled Depths

Peschanaya Bay Baikal Lake, Russia.
Credit: Vladislav Sagaidak/ Shutterstock

In terms of depth, Lake Baikal is unrivaled. Baikal is the deepest freshwater lake in the world. At its deepest point, you’d have to dive over a mile — 5387 feet to be exact — in order to reach the bottom.

One of the earliest accounts of Lake Baikal’s depths was written in 1675 by Russian ambassador to China, Nikolai Milesku-Spafarii, who reported that the deepest point was near Olkhon Island where, “a hundred or more fathoms have been measured and the bottom not reached.” In 1797, workers from the Kolyvano-Voskresensky metal factories attempted to measure Baikal’s reaches more precisely. Using ropes and lines, they measured depths along a linear transect from the source of the Angara River to the mouth of the Selenga River. They determined that the deepest point was 4061 feet — a little short of today’s agreed measurement.

A bathymetric survey recording submarine topography took place in 1821 and again in 1876, when the depth was revised to 4504 feet. Echo meters, which rely on the passage of sound through water, were first used in the 1950s and 1960s — giving a new figure of 5315 feet, which was closer to today’s agreed depth.

Volume Matters More

Winter view from Chersky Stone in Listvyanka at sunset over Lake Baikal and the Angara River.
Credit: Prawat Thananithaporn/ Shutterstock

Lake Baikal is also the largest freshwater lake by volume, containing more water than all of the Great Lakes combined. It collects water from over 300 rivers, the most significant being the Selenga River, which winds north from Mongolia. The only outlet river is the Angara River, which carries the lake water to the Arctic Ocean.

If you measure by surface area, however, Lake Baikal takes seventh place at 12,248 square miles. Three of the five Great Lakes (Huron, Superior, and Michigan) are larger. In fact, the largest “lake” in the world is the Caspian Sea, but because it is technically saline and Baikal is so deep, Baikal holds the greatest amount of freshwater. The lake, containing a fifth of the world’s freshwater, is so important to Russians that they celebrate Baikal Day. This holiday, commemorated since 1999, takes place on the fourth Sunday in August.

An Incredible Ecosystem

The Baikal seal nerpa bask in the sun.
Credit: andreigilbert/ iStock

UNESCO recognized Lake Baikal as the “most outstanding example of a freshwater ecosystem” and named it an official World Heritage Site in 1996. In summer or winter, the water — or ice — is exceptionally clear. This clarity is a consequence of plankton that eat floating debris and a lack of mineral salts in the lake.

Lake Baikal is rich in biodiversity and people often refer to it as Russia’s Galapagos. Brown bears, wolves, moose, reindeer, wild boar, and marmots live in the countryside around the lake and the skies teem with birds. The lake is home to about 60 species of fish, including omul, which is popularly served smoked in Russia.

In the water, you’ll also find a sizable population of Baikal seals, also known as Nerpa seals. No one quite knows how the seals arrived in the area (it’s possible they swam along a river) but in the absence of predators, these little seals have thrived in Baikal’s waters for a couple of million years. They’re shy creatures and hard to spot in the wild, which only adds to their allure.

A Winter Gem

Bubbles of methane gas frozen into clear ice in Lake Baikal.
Credit: Strelyuk/ Shutterstock

Though many Siberians flock to the lake during the summer to swim in its cold water, Baikal is a spectacular sight in the winter. While many places in Siberia are much colder, temperatures still average -6 degrees Fahrenheit. The ice covering the lake can be as much as six feet thick and hangs around until late spring. The lake is also a methane storehouse and as temperatures plummet, white bubbles of gas freeze suspended within the clear ice. The ice itself takes on numerous forms: giant ice shards, icicles hanging from cave ceilings like stalactites, vertical blocks of translucent ice, and nature’s greatest, open-air skating rink.

When the ice is thick enough, usually from mid-February to late March, an ice road known in Russian as a “zimnik” connects the shore with Olkhon Island. About seven miles long, the road opens up a world of frozen waterfalls, glittering ice caves, and frost-encrusted cliffs which would otherwise be cut off from the surrounding area.

A Summer Retreat

View of Lake Baikal from Olkhon Island, a summer landscape.
Credit: JuNikaCartoons/ iStock

Lake Baikal and the closest village of Listvyanka are also popular destinations in summer. Domestic and international visitors come to cool off beside the lake and follow its pretty hiking trails. Visitors can learn more about the lake’s nature and exploration history at the Baikal Museum.

In contrast, Olkhon Island attracts those hoping for a quieter retreat. Its largest settlement, Khuzhir, has only a few thousand permanent residents. The island’s beaches are ideal for relaxation, and the water is usually calm enough for kayaking. Viewpoints of the lake at Khoboy Cape and Burkhan Cape are no secret, though they tend to be quieter in the morning before the day-trippers arrive.

Over half of the lakeshore falls within the Buryatia Republic. For centuries, yurt-dwelling Buryats have reared goats, sheep, camels, cattle, and horses in the area and worshipped nature in solitude. Today, many in Buryatia retain those traditions and welcome visitors keen to listen to folk music and learn how to cook typical Buryat dishes like lapsha (noodle soup), pozi (dumplings), and salamat (sour cream cooked and thickened with flour).

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