Is Russia’s greatest national treasure under threat?
Lake Baikal in Russian Siberia is the oldest and deepest lake on the planet. It contains 20% of the world’s fresh water. Its incredibly clear and clean water is home to hundreds of unique animal and plant species. Biologists, however, are increasingly concerned about the region’s ecology. James Brown goes back to Baikal 7 years after his last visit to see how the lake has changed.