Hedgem0ny, longtime Bungie fan and amphibious storyteller, was reminded of something from Halo 3 at about 30 seconds into the video from yesterday and decided to elaborate:
Hint: it's the memorial hologram suspended in the Halo 3 map, Epitaph. Whatever that structure is in Destiny, it's definitely beaming with the ancient civilizations and mysterious intelligences Bungie is known for... Unless it's just the Fallen's outhouse.