Russian’s say “Sacred Lake” (their nickname for Lake Baikal) is at least 25 million years old, the oldest lake on the planet. It is also the deepest lake, holding more water than all of North America’s Great Lakes combined. Baikal’s aquatic life includes more than 1,500 animal species and 1,000 different plants, two-thirds of which are endemic. According to marine scientists, Lake Baikal is more biologically diverse than other lakes because oxygen-rich water circulates from its surface to its deepest depths, a process likely related to Geothermal Vents deep below the lakes surface. Lake Baikal is also very unique because the majority of the species that live within it are exclusive to the lake. These sponges, coral, plants and marine life do not exist anywhere else on the planet; if they were to die then the world’s biodiversity would be severely affected. Even in spring, Lake Baikal is covered in snow, its deep waters sealed beneath three-foot-thick ice. The ice will slowly thaw into summer in a process punctuated by cracking sounds not unlike the sharp report of guns. As long as the ice remains in place, though, scientists can set up camp right in middle of this 400 mile long, 5,000 foot deep lake. For a diver to explore below the surface during this time of the year is another story. During much of the year, those who dare must use a small metal saw to cut a small hole in the ice. Then a circular, manhole-size opening is cut with a chain saw and long poles are used to push the round slab under the ice. To keep the hole from freezing over, it must be constantly raked in a team effort. Under the ice, the water is warmer than the air (36 degrees F), but still very cold for scuba diving. Divers must regularly tug on safety lines attached to their wrists to let the crew above know that they are all right. From July to October, however, it’s often possible enjoy diving excursions in certain areas that are completely thawed. Be forewarned; the lake never gets warm. One of the most interesting animals in the lake is the Baikal seal, or Nurpa, the world’s only fresh water seal. Nurpas use their sharp claws to carve dens for their families while ice is still forming. Finding their dens is relatively easy, identified by air bubbles trapped in the ice after being exhaled by Nurpas. You can also look for small breathing holes poked into snowdrifts by the seals. Nurpas are shy and pups resting on a bunk bed of ice quickly dive into the water when startled by a visitor. Green spires of yard (1 meter) tall candelabra sponges poke through the algae. These large spongest that get their color from algae living symbiotically in their tissues, are not rare in saltwater, but not in freshwater lakes. The sponges are homes for amphipods, alien-looking shrimplike creatures - the waters of Lake Baikal hold 240 species - that are as small as grains of sand or can be as large as human thumbs. Hiding among the sponges and algae are sculpins, bottom-dwelling fish that are masters of camouflage, their patterned bodies blending in with their surroundings. These ancient fish, like most cold-water species, don’t move fast. So, the lake’s 40 species of sculpins, comprising 80 percent of Baikal’s fish biomass, rely on camouflage for protection against larger fish. Near the lakes northern and, at a depth of approximately 1,350 feet, a geothermal vent provides warmth for the community of sponges, snails, worms, and fish living in the pitch-dark environment. The existence of this vent confirms that Baikal is a place where continental masses are being pulled apart. UNESCO (United Nations Educational, Scientific and Cultural Organization) has chosen Lake Baikal as one of its World Heritage sites. Lake Baikal is within a suburban area of Siberia and as a result it’s very accessible. It is a huge tourist draw for this area of Asia and there are several ways to travel there, including railway, air and rented vehicles. Nizhneangarsk Airport is located towards the northern tip of the Lake and from there you can travel on the mainline railway service to a number of focal points of the lake. Alternatively, you can fly to Irkutsk Airport at the south end of the lake. If you wish to explore the area of Asia surrounding Lake Baikal first, then your best move is to take the Trans-Siberian Railway service which makes a main stop at the lake. Listvyanka, located in Irkutsk, is the primary tourist destination.