Baikal is the deepest fresh-water lake in the world— at its very deepest some 1,642 meters from top to bottom. That's the same as 909 people standing on each other's shoulders, starting from the poor guy standing on the bottom of the lake, all the way up to the last person at the surface. Can you imagine trying to dive down that deep, over 1.5 km?

The water in Baikal is famous for being so pure and transparent. If you are traveling on a boat, and you drop something overboard, you can see it float down into the lake to a depth of over 40 meters, before it finally disappears from sight. Think of that! It is as if you dropped a feather from a 19-story building and watched it slowly float all the way to the ground below. Do you know of any lakes in your region where the water is that clear?

One of the reasons that our lake is so clear is because of millions of small shrimp-like animals called Epishura. These tiny crustaceans are all over the lake, and eat up floating particles and filter out the lake, keeping it pure and very transparent.

Baikal is not only a deep lake. It also covers a very larger surface area. Overall it spans some 31,722 km²—which means that it is about the same size as the entire island of Taiwan!

From north to south the lake stretches 636 kilometers—which is about the same distance as between the cities of Shanghai and Wuhan! Baikal is quite narrow, however, averaging only 50km across. So in many places you can look across the lake and see the shoreline on the opposite side.

It might be hard to imagine, but some 8 million years ago the region around Baikal was more or less sub-tropical, with temperatures almost 14C higher on average than they are now. The warmest and sunniest place on Baikal is on the west coast north of Listvyanka, where in the summer it will average around 22-25 degrees Celsius during the day.

If you really like to hike and you decided to walk along the entire shoreline all around Baikal, you would need to trek over 2,200km to circle the entire lake. This would be like walking from Beijing to Wuhan—and then all the way back!

Here is an unusual fact: there are 300 rivers and streams that flow into Baikal; but there is only one that flows out of the lake, the mighty Angara River.

Even though the Angara is a big river, it would take some 400 years for this river to empty out all the water in Baikal. In other words, a drop of water that flows into Baikal will stay there for four centuries on average, before it finally escapes out through the Angara on its way to the Arctic Ocean. That's how big the lake is!

The lake itself is amazingly rich in bio-diversity. There are around 2,600 species of animals, fishes, and plants at the lake. And more than half of these are uniquely endemic, appearing nowhere else on our planet.

Most lakes in the world only last some 10,000-15,000 years before they fill up with sediment and disappear. But Baikal is very old, perhaps as much as 25 million years old. The surface of the earth here is pulling apart, which means that the lake keeps on expanding and changing its shape over time.

Most people don't realize that much of the larger Baikal watershed lies to the south, inside Mongolia. The largest river flowing into the lake is the Selenga, where the source lies some 1,024 km up-river, in the mountains of Mongolia. More than half of the water coming into Baikal enters through the Selenga.

Some of the fish in Baikal are very strange-looking. The famous "golomyanka" fish is almost transparent, made up of 40% pure fat. This fish is also very unusual in that it gives birth to live baby fish, instead of laying eggs.

Lake Baikal is mostly surrounded by mountain ranges. The lake shores lie some 456 meters above global sea level, and the nearby mountains will rise thousands of meters higher.

Winter weather at Baikal usually sets in during November. But the lake doesn't completely freeze over with ice until the end of January. The last ice floes on the lake usually can be seen in the far north even in early June. With recent global warming, evidence shows that the lake is freezing later and later every year, and thawing out earlier in the spring as well.

The ice can get quite thick on the lake, anywhere from 70 centimeters during warmer winters, up to 150 centimeters thick during the colder winters that used to be more prevalent in Siberia. The entire lake always freezes over, except for a tiny patch of blue water that remains unfrozen at the mouth of the Angara River.

During stormy weather the waves at Baikal can be massive, up to 4 meters high!

Baikal is also known for its many islands, some 27 in all. The largest of them is Olkhon, which is the only island where there are villages and settlements. Olkhon is actually quite a huge island, some 71km north to south, and 12km across.

Often on the lake the weather can be unsettled, with winds coming from every direction over time. Some of these winds are famous, and actually have names. For example, the Barguzin is a crosswind that rises up out of the valleys to the east of the lake. Then there is the Sarma wind, which can often reach hurricane levels of 40 meters per second. Most people prefer the lighter Selenga winds, which will bring up warmer air from the Mongolian steppe-lands to the south. Finally, when there is fog shrouding the Khamar-Daban Mountains, you will often get a Kultuk wind blowing in from the southwest.

The name of the lake, Baikal, probably comes from a local Turkish dialect, where the words Bai-Kul mean "rich lake." Other nearby lakes in Russia have similar name origins, such as Issyk-Kul ("warm lake") and Kara-Kul ("black lake"). There are many who think the name might have come from Mongolian, but that theory is now more doubtful. The local native people have their own names for the lake: for the Buryats it is Baigal-Nuur; and for the Evenk tribes the lake is simply called Lama.