In the history of the Earth there have been five other attempts for Life to create intelligent life. Millions of years separating them... Atlantis may not be a myth, just didn't happen in our time. Civilizations don't overlap.
Three of those civilizations were destroyed by natural causes, and two of those by the civilization itself... parallel with the current humanity and its civilization a civilization of caterpillars.
Our civilization is heading toward the same self-annihilation, unless... Unless human being happens.