7. The faces of the show’s creators David Benioff and Dan Weiss were two of the faces Arya sees when she enters Hall of Faces.
The easter eggs were designed by prosthetics supervisor Barry Gowen. One of the faces Arya touches at one instance in the scene was his mother. For the set they have created as many as 600 faces of different sizes, shapes, colors and ethnicities.(source)
8. Peter Vaughan, who plays the blind Maester Aemon, is partially blind.
The 93-year-old actor acted in many roles including Winston Churchill, the German Nazi figure Alexander Izvolsky and Hermann Goring. His character, in Game of Thrones, Maester Aemon gives up his claim to the Iron Throne after his father dies in a battle. Instead he joins the Night’s Watch pursuing knowledge and wisdom as a maester.(source)
9. According to G. R. R. Martin the north of the Wall is as large as Canada.
Beyond the Wall is a large area of land which was part of Westeros. The building of the wall essentially segregated it from the rest of Westeros because of its supposed uninhabitable conditions. The wildlings, or free-folk as they themselves refer to, live a very nomadic life because of the cold and the dangers associated with it. The danger of White Walkers were entirely forgotten by the rest of Westeros, thinking them a myth and changing the Wall’s objective to preventing wildlings from entering the south side.(source)
10. Peter Dinklage and Sean Bean were the first choices of the show writers for the roles of Tyrion Lannister and Ned Stark.
For the rest of the characters there was an extensive amount of auditioning. Some of the actors were recast after the pilot was filmed. Michelle Fairley replaced Jennifer Ehle for Catelyn Stark and Emilia Clarke replaced Tamzin Merchant for Daenerys Targaryen. The writers also had to conduct auditions for subsequent seasons as there were always new characters.(source)
11. Dire wolves actually existed during Ice Age. They were bigger than present day grey wolves and had very large teeth.
According to the fossils found in the natural asphalt pits in Hancock, Los Angeles, they have existed and became extinct about 16, 000 years ago. The fossils are known to be found in great numbers in North American regions, especially California and Florida.(source)
12. The series was filmed in Titanic Quarter, Ireland, where RMS Titanic was also built.
It is also home for many film studios, apartments, educational institutions, entertainment, and, of course, Titanic-themed attractions. It was in one of the studios known as Titanic Studios or Paint Hall Studios that the Game of Thrones shoot was done.(source)