Karakter Design Studio, Game of Thrones' VFX concept art team, has just released a treasure trove of art from season 4. While locations like Braavos (above) and King's Landing look great, it's the art from North of the Wall that is the most captivating.
Karaktor's not only put the art online, but there are also quotes from the artists explaining some of the design choices. For Moat Cailin:
The set we had available for Moat Cailin did not match the description in the books, but it gave us the opportunity to design the castle after a Motte and Bailey model, which is not just a nice phonetic match, but also a castle type that fits the world perfectly.
TOBIAS MANNEWITZ, VFX CONCEPT ARTIST
And for the wights:
The visual design of the wights had to tell a story, so everything had to make sense: What kind of people could have died north of the wall? Some had died a long time ago, which gave them the look of an ice mummy.
ROBERT SIMON, VFX CONCEPT ARTIST
And the Child of the Forest:
The Child of the Forest design was a tough nut to crack: It's design was an open field, so we had to develop many options to find the right one. We had to avoid the look of an elf or a fairy, while keeping the physiognomy of the actress unchanged.