Step 1 : Introduction to the question "The deepest lake in the world, Lake Baikal, is in which region of Russia?"
...Located in the mountains of southern Siberia, just north of the Mongolian border, Lake Baikal contains 20% of the world’s fresh water. It’s the oldest freshwater lake in the world, dating back 20-25 million years. Lake Baikal is home to the world’s only true freshwater seal species, aptly named Baikal seals. The area is known for wildlife watching on the hiking trails, and in the wintertime, dog sledding is a popular activity.