I'm just curious what people think. Clearly we don't have much in the way of writings from that far back (anything, in fact).
I just wonder if you consider that it was during an ice age. Water levels were lower. The Earth was somewhat cold. Maybe only bearable at the very lowest possible altitudes. But, of course, the lowest altitudes are the ones that got covered in water when the ice age ended.......
How easily do you think an advanced civilization could escape our archeaological notice? Not advanced like we are now, or anything, of course, but maybe to the point of writing?