A new behind-the-scenes visual effects reel has revealed how the Night King's army from Game of Thrones' penultimate season seven episode was created. The video shows how practical effects were melded with computer-generated graphics to create a fantastical icy tundra, hordes of ravenous corpses and dragons, both living and dead.

[EMBED_VIMEO]https://vimeo.com/232009905[/EMBED_VIMEO]

The video was released by El Ranchito, an award-winning effects company known for its work in television and film. El Ranchito has worked on films like Agora, The Impossible, A Monster Calls and, of course, Game of Thrones.

The video focuses on the Battle Beyond the Wall from Game of Thrones' penultimate season seven episode, in which a disparate team of warriors band together to try and capture one of the thralls under the control of the White Walkers. In the episode, the team ends up surrounded on an island in the middle of a frozen lake, encircled by the dead army until the horde starts to advance. The ice cracks, and zombies start pouring into the frigid waters below.

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For all the show's green screens and postproduction tweaking, some actors still had to plunge waist-deep into pools of water to achieve this shot. Computer-generated dragons might be one thing, but it seems Game of Thrones still relies on practical effects for certain shots.

Game of Thrones' seventh season recently concluded. The show will return for its eighth and final season at a later, undisclosed date.