I just saw Valerian The City Of A Thousand Planets it was so good! I came up with a theory for it too. I believe that in Valerian, it took place after a nuclear war between the U.S and the Soviet Union. When watching the movie, it said that the main problem was the humans fighting the war. With bombs. They show what happens and you can see them launch them too! Also, when the are walking towards the emperors son. Next to Valerian and Lauriline is some sort of ship wreckage thing with Soviet Russia's flag on it and the comic was written during the Cold War era so it only seems fitting.
Plus, we know that this is between earth countries because in the commanders office, behind him is the flag of almost every country in the world, yes I checked each one...
It was a very painful experience. So, what do you think? Am I right or is this just bullsh*t. Tell me please. Ok bye my little potatoes!!!!