If you watched the Game of Throne’s season seven premiere (and I have to imagine you did if you're bothering to read this article), then you'll probably remember Sandor Clegane, AKA The Hound staring into a fire and envisioning a wall of ice. Specifically The Wall.
Kind of a sad moment because the scene follows the demise of the family he'd left to starve in season six, but the emotional heft of the situation no doubt led the Lord of Light to give The Hound insight that could change everything... 
No, what he saw was the army of the Night King marching AROUND the wall.
Naturally, fans were confused because, why the hell didn't the White Walkers just go around the wall before? Kind of defeats the purpose of even having a wall...
Now, get ready to have your mind f**king blown. Via Redditor sleuth, RohitMSasi...
Look at this shot of the opening credits from Season 6, Episode 1.
Ok, now compare it to this shot from Season 7, Episode 1. What do you see that's different?
Obviously, the size of the zombie army has grown, but there's something else. THE SEA IS FREEZING!
S**t is about to get heavy.
What do you think? Valid theory or fanboy nonsense?