The eight seasons of Game of Thrones are based on George R.R. Martin's A Song of Ice & Fire novel series, but the TV series doesn't actually make it to each of the well-known castles from the books.

The Eyrie is seen in Game of Thrones as the most impregnable castle in Westeros. The Eyrie's layout may keep invaders out, but it struggles with long-term defense. Moat Cailin and Casterly Rock ...