Forget White Walkers, dragons or the Lord of The Light, Game Of Thrones’ most guarded secret could actually be a teleportation device that the characters have been using.
For the past six seasons, Game of Thrones fans could only speculate. But after the events (or the lack of, for that matter) in episode 3 of season 7, fans are sure that some Deus Ex Machina is in play behind the instant apparition of GoT characters, transcending unity of time place and action.
How else would you explain THIS as the very first scene?