Dreams.

I had a dream about a full-scale medieval conflict between the peoples of Europe and its surrounding regions against alien humanoid invaders, resembling Tau or Protoss in skin color and armor. I wandered through the mountains, plains, and hills as an unarmed refugee, fleeing the war, and occasionally stumbled upon remnants of battles. I noticed that the colder the region from which the next army of Earth's fighters originated, the more fiercely they fought, and the warmer the region, the less fiercely they fought. In the latter case, it didn't reach outright collaboration, but its theoretical possibility was felt somewhere on the edge of perception, which caused all the Earth's armies, despite the difficult situation, to distrust each other even more.