"Game of Thrones" filming crew sure takes a lot of effort to actually decorate and make the sets real rather than make it all CGI, as we found out a few weeks back. But the dragons and massive armies though? It all looks as real as it can get, too.
Pixomondo surely made a really great job with that, and the newest FX reel for "Game of Thrones" season 3 shows how Daenerys's dragons evolved layer by layer from a tennis ball on a stick. Additionally, those final shots of the "Mhysa" episode are illusions as well, with Dany's thousands of Unsullied copied multiple times.