Try to think up a premise that sums up the whole story in one sentence, without too many details. The bizarre stuff can be added through the Palette.
(Are you OK with me randomly plopping into the thread to dispense
I am not only totally ok with you popping up and giving advise, it is very much appreciated.
I was thinking that Atlantis rises to unknown hights (by whatever means) bit finally withers/disappears and the world that we know starts somewhere in the early ages. There are several 10.000 years humankind existed before the Iron Age. On tha other hand Industral Revolution happened in only 500 years, so there is plenty of time Atlantis could have happened. And since this is our game, we don't need to be restricted by "real history" at all if we choose not to.
"The highly advanced Culture of Atlantis existed in the early Ages, but disappeared before the beginning of the Bronze Age."