Russia (Eastern Europe)

The thing about Russia is that while it grew in population and continues to grow, much of the landmass of Siberia is still... well... unpopulated. I was debating things like climate change melting it back and leading to more landmass, but at the same time... why not the opposite? What if Siberia actually grew outwards, forcing much of the Asian continent into colder climate? Siberia itself can remain an expansive region with... oh, I don't know, hidden bases and things of that nature... but it still remains the tundra it always was.

Key cities and regions:
 * Moscow Where would Russia be without Moscow, the capital and most populated city. The population of Moscow is higher than  all of the other cities in Russia  combined.  It's the central point for the whole ordeal.
 * Saint Petersburg Saint Petersburg follows up as the second most populated. In comparison to Moscow, Saint Petersburg is not a sprawling city. It was a target of a weapons attack during WW3 and a lot of the structures were torn apart. For a while, it looked like a literal warzone. Now that much of it has been repaired, it somehow manages to keep a lot of the old architecture, but many of the buildings have been added onto with entirely new structures made of metal and carbon. Looking at buildings such as the Trinity Cathedral almost reflects the rest of the world, half machine and half earthen, in its own twisted way.