Lake Baikal

Baikal holds roughly a fifth of all the unfrozen fresh water on Earth's surface — more than all five of North America's Great Lakes combined — despite a surface area that's a fraction of theirs, because the lake plunges to a maximum depth of about 1,642 metres, deeper than almost any point on the ocean floor within a thousand kilometres of shore. It's also old in a way lakes almost never get to be: most lakes on the planet are geologically short-lived, filling with sediment within tens of thousands of years, but Baikal sits in an active continental rift that keeps deepening it faster than it can silt up, and it's been open water for an estimated 25 million years.

That age is why roughly 80% of the species found in the lake exist nowhere else on Earth. The strangest of them is the golomyanka, a nearly transparent fish with no swim bladder and a body that's up to 40% fat by weight, adaptations that let it live and reproduce at crushing pressure a kilometre or more down — it's essentially the only fish species alive that has fully committed to the lake's abyssal zone as a permanent home. Just as odd is the Baikal seal, or nerpa, the only seal species on the planet that lives its entire life in fresh water rather than the sea; nobody has fully explained how an ocean-adapted animal ended up landlocked here, though the leading guess involves ancestors swimming up a prehistoric river system from the Arctic long before the rift lake took its current shape.

In winter the lake itself puts on a display that has nothing to do with its biology: ice several feet thick forms so clear you can see fish swimming metres below it, and as the ice sheet expands and contracts with temperature swings it cracks under enormous tension, producing booming, almost musical groans that carry for kilometres across the frozen surface — a sound locals simply call "Baikal singing."

Best time to visit

Late February to March is peak season for the clear ice phenomenon and ice-road access to islands like Olkhon; July and August are the reliable window for open-water and hiking visits.

Getting there

167 km from Ulan-Ude. Baikal International Airport (UUD) is about 171 km away.