Five giants sat in a circle in a meeting to discuss the future of civilization.
Their prophesies descended from the sky and must be written on stone.
Atlantis has just been lost, and they must record this catastrophe so that humanity can survive in the future.
Each giant must prophesize for each nominated period in the sky. They must prophesize well to ensure that their leader does not die when the same disaster returns in the future. They know the date.
Upon completion of the prophesy, they scatter around the world, placing their stone tablets encased with precious gems and gold where they may lay hidden until the 21st century for humanity to find.
But you have to believe in order to find it.