Following is a transcript of the video. Narrator: Most of us know what a dragon sounds like, but they don't actually exist. And none can stop me! So, how does Hollywood know how to make them sound?

How does sound help Drogon and Toothless come to life? Sound designers for "Game of Thrones" and "How to Train Your Dragon" have to get creative in order to invent the sound of a dragon. By layering ...