A ceiling of transparent ice with pressure cracks running through it like glass sheets, blue light coming through from above…A ceiling of transparent ice with pressure cracks running through it like glass sheets, blue light coming through from above, and visibility of 40 metres in water that is almost distilled. Baikal seals, omul and golomyanka live here and nowhere else, and the shoreline ice caves at Olkhon freeze into turquoise vaults. Baikal is a rift lake 25 million years old, the oldest and deepest on earth, and around 80% of its animal species exist nowhere else, including the world's only exclusively freshwater seal. Winter ice thick enough to drive a truck across is what makes the diving possible. Anchorage: Boats work Maloe More in summer only; from January the lake is a road. Hazards: Ice diving under a metre of ice at zero degrees, on a line, in a drysuit. Nothing about this is casual. Altro