Can we all talk about the woman Eren saw in his flashback for a moment (the one people are apparently calling Geographia)
I have seen some very interesting theories, my favorite being that memories pass down from coordinate to coordinate, thus explaining what Eren's father said about memories. Maybe that's what "To You, 2000 Years From Now" meant. The "you" is not the author addressing us, but a previous coordinate addressing Eren (but what really messes with that theory is that titans have only been around for 100 something years but whatever. Perhaps titans have a longer history than we thought).
Another thing I've seen is that perhaps Christa was the intended coordinate as maybe the Reiss family held all the coordinates, but something happened where Eren ended up getting it instead. Maybe Eren's father was going to visit the Reiss family in the beginning of the story? I've also seen some mentions that perhaps Eren is remotely related to the Reiss line.
Anyway, who is this woman? Why does she look like Christa (to Eren)? How does this relate to Eren's titan abilities? And does this tie in to how Eren seemed to see an older Mikasa at the very beginning of the manga but then awoke to a young Mikasa?