As any unemployable guitar player idly channel-hopping day time satellite TV documentaries
should know..

..one recent theory of a sudden world wide ancient mega flood event
posits the idea of a tremendously huge sheet of Arctic Glacial ice breaking off
and causing such a cataclysmic tsunami
that all key civilizations from the mediteranean [overflowing and engulfing the Black sea hinterlands]
to the coast of India and beyond , were devasted within mere hours... or something like that...???

Oh and that's when Atlantis sunk as well..
but that's another speculative documentary..
and I wasn't really paying attention as I was too busy looking through the front room curtains
watching the police car & ambulance outside the junkie flats across the road...