Almost every outdoor scene in HBO's hit fantasy epic Game of Thrones is created using computer graphics. We know this not because the use of CGI is obvious (on the contrary, the castles and forests are particularly convincing), but because we just watched the above video which shows the environments of the series before and after they were doctored by a special effects company called BlueBolt. Warning: there are some spoiler alerts toward the end for the uninitiated.

[Geekosystem]