Olga Kamenskaya / Baikal seal (Pusa sibirica) pup on ice, endemic species. Lake Baikal, Russia, April.

Ingo Arndt / Sun rising over ice formations on Lake Baikal. Siberia, Russia. February 2019.

Michel Roggo / Meltwater channel through icefield in the Temnik River, Baikal Nature Reserve, Buryatia, Siberia, Russia, May 2015.

Michel Roggo / Autumn trees viewed from below Lake Baikal, Lake Baikal UNESCO World Heritage Site, Siberia, Russia. May 2013. Photographed for The Freshwater Project.

Olga Kamenskaya / Pebbles reflected in the water surface at mouth of Sheryldy river, Lake Baikal, Siberia, Russia. September

Olga Kamenskaya / Endemic freshwater sponge (Lubomirskia baicalensis), Lake Baikal, Siberia, Russia. October.

Olga Kamenskaya / Endemic sponge (Lubomirskia baicalensis), Lake Baikal, Siberia, Russia. September 2013

Olga Kamenskaya / Clouds over Lake Baikal, Siberia, Russia, October 2010.

Olga Kamenskaya / Transparent ice formation on Lake Baikal, Siberia, Russia, March 2012.

Olga Kamenskaya / Ice formations on Lake Baikal, Siberia, Russia, March 2012.

Olga Kamenskaya / Coast of Olkhon island, Lake Baikal, Siberia, Russia, September 2013.

Olga Kamenskaya / Ice formations in snow on Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Ice formations on Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Wide angle view of vehicle parked on ice on lake surface. Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Clear pane of ice on Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Ice formations on Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Vehicles parked on ice on the surface of Lake Baikal, Siberia, Russia, March 2008.

Olga Kamenskaya / Baikal seals (Pusa sibirica) hauled out on rock. Endemic to Lake Baikal. Russia, May.

Olga Kamenskaya / Snails (Baicalia turriformis) Lake Baikal, Russia, August.

Olga Kamenskaya / Amphipod (Acanthogammarus victorii), Lake Baikal, Russia. June.

Olga Kamenskaya / Diver with Baikal sponges (Lubomirskia baicalensis). Lake Baikal, Russia, March 2007. Model released.

Olga Kamenskaya / Man looking through transparent ice (1m thick) on lake surface to see diver below. Lake Baikal, Russia, March 2008. Model released.

Olga Kamenskaya / Young Baikal seal (Pusa sibirica) at breathing hole. Lake Baikal, Russia, April.

Olga Kamenskaya / Young Baikal seal (Pusa sibirica) at breathing hole. Lake Baikal, Russia, April.

Olga Kamenskaya / Ice stalagmites / ice spikes formation, Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Ice splash out formation with icicles, Lake Baikal, Siberia, Russia, March

Olga Kamenskaya / View of people standing on ice from underneath car, on the ice of Lake Baikal, Siberia, Russia, March. Property released and Model released.

Olga Kamenskaya / Mini van crossing over pile of ice on Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Mini van crossing Lake Baikal ice, Siberia, Russia, March.

Olga Kamenskaya / Car on thick Lake Baikal ice, Lake Baikal, Siberia, Russia, March. Property released.

Olga Kamenskaya / Ice pile of broken shelf ice, near the shore of Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Pyramidal ice fragment reflected on the surface of Lake Baikal. Ice fragment acting as a prism refracting light into rainbow. Siberia, Russia, March.

Olga Kamenskaya / Ice fragment reflected in the ice of Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Ice fragment reflected in the ice of Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Ice fragment on crack in Lake Baikal ice, Siberia, Russia, March.

Olga Kamenskaya / Man looking into ice hole dug for ice diving, Lake Baikal, Siberia, Russia, March. Model released.

Olga Kamenskaya / Clear panes of ice on Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Clear pane of ice, Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Cracks in the ice of Lake Baikal, Siberia, Russia, March.

Olga Kamenskaya / Cracks in the ice of Lake Baikal, Siberia, Russia, March.

Eric Baccega / Buriat shaman plays tambourine on Olkhon Island, Baikal lake, Siberia, Russia, June 2000

Mark Brownlow / Mark Brownlow, producer of Freshwater programme for BBC Planet Earth series, behind ice sheet, on location at Lake Baikal, world's deepest and oldest (and largest by volume) freshwater lake, Siberia,...

Mark Brownlow / Rebreather instructor Ian Thomas and cameraman Didier Noirot prepare to dive under the ice, Lake Baikal, world's deepest and oldest (and largest by volume) freshwater lake, Siberia, Russia. BBC Plane...

Mark Brownlow / Looking down on frozen surface of Lake Baikal, world's deepest and oldest (and largest by volume) freshwater lake, Siberia, Russia. BBC Planet Earth series, April 2005

Konstantin Mikhailov / Chivyrkuyisky Bay, Zabaikalsky NP, Lake Baikal, Russia.

Doug Allan / Cape Burchan, Lake Baikal, Russia.

Konrad Wothe / Baikal Seal (Phoca sibirica) resting on rock, Zabaikalsky National Park, Ushkany Islands, Lake Baikal, Russia

Konrad Wothe / Baikal Seal (Phoca sibirica) resting on rock with flipper raised, Zabaikalsky National Park, Ushkany Islands, Lake Baikal, Russia