By Steven Eke
BBC correspondent in eastern Siberia
Lake Baikal in Siberia is one of the world's most special water reserves.
It's said to be home to one fifth of the earth's fresh water, and is the unique habitat for many species of animals, plants and fish.
Baikal is also known as "the pearl of Siberia"
Travelling to this part of eastern Siberia, I was open-minded as to whether Baikal really would live up to expectations.
I had seen many wonderful photographs, read countless tales of its beauty.
However, there are many places in Russia that fall far short of the guidebook descriptions of them.
But Baikal is majestic.
Its waters, frozen much of the year, remain strikingly cold even during summer months.
In some places, the lake has steep, taiga forest-clad banks. In others, deserted, rocky shores.
Few tourists visit the lake because of its remoteness
A light mist hangs over much of the lake, creating an eerie, yet calming view.
Moving away from the shore, the lake remains remarkably transparent for a long time.
The local authorities want tourists to come.
But inhibited by the long distance, the remote territory and the peculiar backwardness of much of the region, few do.
Perhaps that is just as well.
The "pearl of Siberia", as it is known, continues to have an almost mystical attractiveness.
It was here that Russia's environmental movement was born.
Early campaigners demanded the Soviet Government close the 1960s Baikal'sk Pulp and Paper factory.
Then, as now, it pumped industrial effluent into Baikal's precious waters.
The factory has been pumping industrial waste into Baikal for decades
The factory is as unpleasant inside as it is shockingly ugly on the outside.
I went to visit it, the factory's management keen that I see how it works.
Inside a dark and noisy cavern, old machinery was turning wood and bark chippings into paper.
Condensation dripped from the ceiling while water sprayed from leaking pipes on the floor.
Outside, the "purification facilities" were explained to me.
Stage one involves mechanical filtering. There, the stench was nauseating.
Stage two relies on biological filtering - the water, in theory, already being free from physical contaminants.
Stage three is a pond, where water is aerated and held before being returned to Baikal.
I was told that foreigners "react with delight" at what they see. However, stage three smelled disturbingly similar to stage one.
Source of employment
The factory was the response to the Soviet space programme's demand for high-quality cellulose.
In the years when economic expediency took precedence over environmental pollution, Soviet planners decided to build the factory on Baikal.
It still stands there today, belching steam and polluting the lake.
A local town of some 17,000 people - Baikal'sk - has developed to service it.
I found few people in Baikal'sk wanted the factory closed down.
To them, it is the only major source of employment.
Campaigners continue to demand the factory's closure.
They're outraged that the World Bank has decided to make more than $20 million available to the factory for "modernisation".
The industrialists claim the greens deliberately exaggerate the damage to Baikal for financial reasons.
Some influential local scientists agree.
Meanwhile, local environmental organisations say official pressure on them is growing.
One has recently found itself raided, and its computers seized, by the FSB, Russia's internal security service.