What evidence there is about the existence of Atlantis?

The Greek philosopher Plato in his works Tinnaeus and Critias describes a land larger than Africa beyond the pillars of Hercules [Gibraltar straights] that its civilization was destroyed by a catastrophic flood 9000 years before his time after a war between the Greeks of Athens and the Atlantis, though some speculate whether the date was mistranslated and was supposed to be 900 years.