Lake Baikal is in Russia. It is the biggest and deepest freshwater lake in the world, and an UNESCO World Heritage Site.
The lake is located in Eastern Siberia, between Irkutsk Oblast to the northwest and Buryatia to the southeast. It is the planet's deepest and oldest lake, as well as its largest body of freshwater, containing over one fifth of the world's supply.
The nearest airport is in Irkutsk, which can be reached from either Domodedovo or Sheremetyevo in Moscow.
From Listvyanka you can go by boat to the Bolshoie Koty, in the hearth of Baykal National Park. One way costs around 180 rubles, but you cannot buy tickets in advance (only in Irkutsk, I think). First boat goes from Listvyanka at 10, last at 16 o'clock. From there you can get by boat at 18.00 or by foot by Baykal tourist trail. It is around 18 kilometres and the most of the path goes around the shore of a lake. From Bolshoie Koty you can go to the Irkutsk by the same boat. It costs around 360 rubles (summer 2008).
From Listvyanka you can go to the Port Baykal that lies on the opposite side of river Angara. Boat costs around 34 rubles and goes from the place just under the Baykal limnological museum. It takes around 5 minutes to get there. However it is recommended to go the other way, from Port Baykal to Listvyanka.
You can go to Port Baykal as well by train. It goes from Sludyanka at the southern corner of the lake. It takes around 4 to 6 hours, since the train is really slow. But you have time to look around, because the railway is going by the shore of the lake. It costs 46 rubles. It is so slow because it is the old Baykal railroad was built around 100 years ago.
Insider travel tip:
The smoked Omul sold by several fish sellers on the edge of the lake is wonderful, and there is a restaurant on the lake's edge with good fish, along with several bars and small groceries. Everything in Listvyanka is within walking distance, including a small post office.