I'm not too surprised. I'm pretty sure no one besides a friend and I are from the same Earth. What is surprising is just how many different Earths I've seen referenced.

[ Ender nods after her question. Of course there are movies, cartoons and books that all explore an Atlantis theme. ]

Yeah, I've heard the name before. 'The Lost City of Atlantis.' A legendary city supposedly underwater...sometimes filled with merfolk, sometimes just an empty shell of a city. Is that your world?