We don't know that it hasn't left any physical evidence behind. The origin of many archaeological artifacts are not known for certain. It's possible that there is pottery and other artifacts from Atlantis that we've already unearthed.
I was commenting in the context of the Eye of Africa, it’s a fascinating structure that happens to have some dimensional characteristics that vaguely resemble Plato’s description. There’s just no physical evidence of any significant architecture there of any kind.
