where is it filmed?
The dragons featured in the episode's finale were implemented by BlueBolt.
Fire and Blood (Game of Thrones)
The dragons featured in the episode's finale were implemented by BlueBolt, the lead VFX agency for the first season. 
game of thrones season 1 episode 10 plot The episode's action revolves around the Starks' reactions to Eddard Stark's execution: Sansa is taken hostage, Arya flees in disguise, Robb and Catelyn lead an army against the Lannisters, and Jon Snow struggles with his divided loyalty. what is the name of this episode you mentioned? Fire and Blood.
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Fire and Blood (Game of Thrones) [SEP] Filming
The dragons featured in the episode's finale were implemented by BlueBolt, the lead VFX agency for the first season. VFX supervisor Angela Barson confirmed that the CGI dragons were among the most stressful effects, prompting sleepless nights. Commenting on the episode's climactic scene where the hatchling dragons are revealed, actress Emilia Clarke told VH1, "You see the relationship that Dany has with her eggs, and you see that grow and grow and grow and kind of the intuitive connection she has with them, you see that develop really beautifully". Clarke also hinted that she expected to "get to play with some more dragons!" in the second season, based on her conversations with book author and executive producer George R.R.