This massive body of water located in Russia is truly remarkable. It is the world's oldest and deepest lake, is the second most voluminous in the world, and contains some of the world's clearest water. It has somehow remained contained for more than 25 million years, and currently holds 20 percent of the Earth's fresh water supply.
Two thirds of the more than 1,700 species that call Baikal home are found nowhere else in the world. It's no wonder that the region was declared a UNESCO World Heritage Site in 1996.