FACTBOX-Lake Baikal, the world's largest lake

(Reuters) - Russian explorers plunged to the bottom of Lake Baikal, the world's deepest lake, on Tuesday in a show of Moscow's resurgent ambitions to set new records in science.

Here are some details about Lake Baikal:

* WHERE IS IT?

-- Lake Baikal is tucked away in the remote hills of south-east Siberia, within the republic of Buryatia and Irkutsk province of Russia, where Russia borders China and Mongolia.

-- Baikal is home to some of the world's rarest types of fish and other water-life. There are between 1,500 and 1,800 animal species at different depths, and hundreds of plant species live on or near the surface. The majority of the species are endemic to Baikal. There are some 50 species of fish.

-- Into the lake flows more than 330 rivers and streams, the largest of which include the Selenga, Barguzin, Upper (Verkhnyaya) Angara, Chikoy and Uda.

-- Industries along the shores of Baikal include mining (mica and marble), the manufacture of cellulose and paper, shipbuilding, fisheries, and timber.

* DIMENSIONS:

-- Its area is some 12,200 sq. miles, with a length of 395 miles and an average width of 30 miles.

-- The world's oldest lake was formed 25 million years ago and contains 20 percent of the world's total unfrozen freshwater, some 5,500 cubic miles.

* TROUBLES:

-- Last April U.S. and Russian scientists revealed that Lake Baikal had warmed faster than global air temperatures over the past 60 years, which could put animals unique to the lake in jeopardy.

-- They said that the lake had warmed 1.21 degrees Celsius (2.18 degrees Fahrenheit) since 1946 due to climate change, almost three times faster than global air temperatures.

-- Baikal's seals, which raise its pups on the ice, could suffer because the animal has several onshore predators.

Sources Reuters/www.britannica.com

(Writing by David Cutler, London Editorial Reference Unit;)