Do you remember the Seraphim Vault? it was a hidden area in the beta versions of Destiny, that was accessible in Cosmodrome on Earth via a series of obtuse and convoluted steps. It made some waves, because it hinted at a great amount of content for the final game (ha, we know how that turned out), and it was just the kind of thing that would go viral, in spite of there not actually being much to do once you actually end up in there.
Anyway, as it turns out, the Seraphim Vault may actually be accessible in the final game too. it’s not fully clear yet- all we have to go by at this point is some screengrabs that a reader sent VG247 (you can check out all of them via the link; one of them is right above), but it is entirely possible that Bungie plans on making this accessible at a later date. Maybe via DLC. Maybe via a raid or a free update.
Who knows. Just, whatever you do, Bungie, do it fast, because this game is starved for content.