Travel the world or check out your favorite map software, snd look at current hot conflicts and recent ones in the past. You have Iraq and Ukraine/Russia which

Travel the world or check out your favorite map software, snd look at current hot conflicts and recent ones in the past. You have Iraq and Ukraine/Russia which are relatively flat, then you have Afghanistan or Iran on the opposite side of the spectrum. Even a flat country can have forests too thick for flying wirelessly or with fiber optics.