'Game of Thrones' Season 3 teaser: Their world returns to ours

Three-Eyed Raven Tease

Behold a new teaser for "Game of Thrones" -- which doesn't show any new footage from Season 3, but may hint at events to come nonetheless.

The promo shows a raven flying over several cityscapes -- including Venice and New York -- while The National's version of "The Rains of Castamere" plays. The tagline is "Their world returns to ours." Toward the end of the clip, the bird is revealed to have three eyes.

Since the video went up, fans have been speculating about the significance of the song, which is connected to a major event in "A Storm of Swords," the third book in George R.R. Martin's A Song of Ice and Fire series. "The Rains of Castamere" has popped up previously in the series as well -- this version played over the end credits of the Season 2 episode "Blackwater."

Season 3 of "Game of Thrones" premieres March 31 on HBO. What do you think of the teaser?