Now that's a subject that's been around for a long, long, time. If you've ever wondered if such an ancient (way, way, back) civilization existed (and you give Plato the benefit of a doubt that he's not lying) then this short clip with Graham Hancock is for you. He sums up the whole subject and brings in some relatively new information concerning the period 11,600 years ago.
Hancock is a world class explorer, in so many ways. He charges into the thoughts that go bump in the night for many.