Perfectson
Banned
This is the walls sole purpose.
By the way, have we discovered how the Walkers plan on getting past the wall? It is big as shyt. Unless they plan on sailing around it, I don't see how the 7 Kingdoms don't have the upper hand here.
Bran has the mark , so apparantly the white walkers can go anywhere he can. Which is why they were able to get into the cave.