It's said Lake Baikal could provide fresh drinking water for the world's entire population for 50 years if all other supplies dried up.
The lake is our first real taste of Siberia after a four-day and four-night journey on the Trans-Siberian Railway from Moscow.
Its frozen surface in winter is desert-like in its vast empty appearance, but offers plenty of activities for adventurers, from ice-skating to ice-fishing and driving.
Our hovercraft experience begins at the pebbled beach outside the food market where the aromatic smell of steamed fish and rice dishes fills our noses and makes our stomachs grumble hungrily.
After a dull diet of powdered mashed potato and two-minute noodles every meal for four days it is something to look forward to on our return.
The hovercraft is a white-knuckle ride of high-speed twists, turns and spins taking just minutes to reach the far side of the lake.
The bright-coloured houses and shops at our starting point look tiny but stand out above the pristine white surface of the lake.
Hovercraft on the Siberian lake. Photo / 123RF
Despite the freezing temperatures, which can reach -35C in the middle of winter, the sun shines brightly and reflects off the lake, making sunglasses a must.
On the lake I explore the surface, brushing aside the soft "snow-cone" ice to see how far below the water runs fresh.
As a trickle of freezing cold water bubbles to the surface I quickly decide that it is a very bad idea.
Closer to the shore, leaves have settled on the surface, leaving perfect leaf-shaped holes as they melt through the layers of ice.
For the adventurers there's the opportunity to hike up the side of the hill, climbing around the side of a railway tunnel to reach a rocky outcrop that hangs high above the jagged ice at the edge of the lake.
Hunger - for food, a traditional sauna and a comfortable bed - draws us back to our home for the night, an almost Austrian-looking chalet part-way up the mountain where we're looking forward to enjoying a traditional Russian sauna - but not before a few last photos from a popular lookout of the stunning lake that has captivated our attention.
After we emerge from the 80C temperatures of the sauna, where tradition dictates you must be thrashed with birch tree leaves before having a bucket of ice cold water dumped over you, snow starts to fall.
Overnight, the mountains around Listvyanka are blanketed with a beautiful dusting of crisp white snow.
The lake is different too. Where the centre had seemingly been frozen solid only a few hours earlier it is now an open expanse of water, small waves peaking on the surface as the cold wind blows.
"That's why we don't walk on the ice," says my British travel companion, with a self-satisfied smile on her face.
Checklist
GETTING THERE Listvyanka is 5000km from Moscow or 70km from Irkutsk in Siberia. It takes five hours to fly between Moscow and Irkutsk. The Trans-Siberian Railway offers a longer, picturesque journey taking four days and four nights.
