A Clash of Kings takes the story to the lands Beyond the Wall, although the first five books do not explore what lies really north ... but we will in the last two books. The TV adaptation used Iceland as filming location for the lands Beyond the Wall. Martin, who has never been to Iceland, said Beyond the Wall was considerably larger than Iceland and the area closest to my Wall is densely forested, so in that sense it's more like Canada - Hudson Bay or the Canadian forests just north of Michigan. And then as you get further and further north, it changes. You get into tundra and ice fields and it becomes more of an arctic environment. You have plains on one side and a very high range of mountains on the other. Of course, once again this is fantasy, so my mountains are more like the Himalayas. In an HBO featurette, Martin stated the lands beyond the wall make up a big part of Westeros, being roughly the size of Canada. The Valley of Thenn is one such location beyond the Wall, and north of that is the Lands of Always Winter, where the Others come from.