Russia's Lake Baikal is the oldest and deepest lake in the world, holding about 20% of the world's fresh water and currently facing increasing environmental threats from climate change and mass tourism. As Russia continues to encourage visitors to the lake, even in the midst of the pandemic, some locals question whether the pristine environment is being sacrificed in favor of revenue. CNN's Fred Pleitgen reports from a town in Russia, where some say their home simply can't take on any more people.