Explanation:

Russian Far East, a region extending between Lake Baikal - world's largest freshwater lake and deepest lake, and the Pacific Ocean.

This is a region situated in the cold Siberian climate but more significantly, it shares borders with China, Mongolia, North Korea and Japan (maritime). On its own, it could be the eight largest - just behind India - in terms of area, and fourth least densely populated country. Both China and the US have been competing to have an upper hand in this region.