Will the sea return and will there be anyone here to see it? ONE hundred million years ago, at the beginning of the cretaceous period, Australia was mostly covered by a vast sea populated with strange prehistoric marine life. Experts warn that the water could one day flow back to engulf the fragile world humans have created, submerging rock and sand beneath a wide, shallow ocean and forcing us out. The return of the Australian sea could be triggered by climate change, a meteor shower, an Ice Age or other natural phenomena, which could strike tomorrow or in millions of years. If we die, will our skeletons become opalized, like that of Kakuru Kujani? If humans survive, could we evolve to live amongst the creatures of the sea and what would that look like?