The Revealer: Clue Number Three

After a brief summer hiatus, The Revealer returns to BackStory this Thursday!  So, you know what that means...the return of The Revealer game.  Longtime fans of the show already know the drill:  in the week leading up to the debut of The Revealer segment, we will post new photographs daily that offer visual clues to the subject of the episode.

Here's the third clue:  Archaeoastronomy brings a fresh perspective to the most studied archaeological site on the planet.

Think you know the focus of this week's episode of The Revealer?  Post your response in the comments section below.