Lake Baikal

The world’s largest freshwater lake by volume, Lake Baikal is also the deepest (max depth 1.6km) and the oldest (25-30 million years). On any reasonable assessment it’s immense – more than 30,000sq km, covering as large an area as Belgium, and holding 22% of the world’s surface freshwater.

Water visibility and oxygen levels are exceptional, even at depths, making it a haven for wildlife. Indeed, it’s famed for its rich biodiversity and endemic wildlife, including the planet’s only freshwater seal.

It also hides a secret every bit as mysterious as the Loch Ness Monster – the Lusad-Khan, or water dragon master, said to resemble a giant sturgeon and depicted in Stone Age carvings on the cliffs that rise above the lake.