If you are willing to accept a pretty sloppily vague definition of Atlantis, the available evidence for this is, in fact, looking pretty good. We have the Piri Reses map of antarctica, we have the various evidences of global trade, and we have the remarkable astronomically referenced architectural congruities in our earliest uncovered cities, all around the globe.
Humans have been effectively the way they currently are for somewhere between 120,000 and 40,000 years, yet we classically think history started in 3000-6000bc. This is the standard assumption, yet it is a remarkably silly assumption.
What happened, I assert, is that any civilizations that might exist before an Ice Age recession, are pretty effectively wiped off this planet each time we have an Ice Age recession, with it's accompanying continual floods and earthquakes. The exact details of when or if atlantis sank, and for what reason, aren't centrally germaine to the loss of an entire civilization.
The most amusing branch of this argument, in my opinion, is the benign conspiracy theory, which holds that the remnants of the atlantis civilization, having survived the ice recession, were, from their point of view, dying from loss of infrastructure and population, and tried to pass on the flame of civilization through monumental stonewriting, and the fostering of secret cults carrying secret instructions to aid in the resurrection of civilization when the time became ripe. Hence, the Egyptian mystery cults passed on the treasures and knowledge to the Templers and/or the keepers of the Ark of the Covenent, when they established outposts in the Holy Land, who, in turn passed on their legacy to the Masons when their order was, in turn, threatened with extinction, and the masons, following their ancient orders of battle, were instrumental in the establishment of the US Constitution.
Any who doubt this need merely observe the tribute to the Masons, the pyramid on the dollar bill, for verification.
Anybody listen to the Art Bell guest last night talking about 300 million year old human skeletons and devolution?