Plato was first and formost a storyteller. The city he was describing was the "current" Athenian ideal of the perfect city. A place unlike the athenian city states that was unassailable and had an infinite supply of food minerals and material wealth. For the purpose of the challenge this is the source of the original golden age myth. Did Atlantis exist? No doubt there was a city at one time just like Troy or Camelot. But every one puts their own spin on the legend. Mallory and White's version of Camelot differ greatly from Lerner and Lowe's. Ther grail in old english was a stone of the original Celtic seven and not the cup of Christ. The Atlantean saga had several thousand more years to be corrupted by local politics, religon, etc. Everyone has a flood story from Greece to Africa and into India, Most of the religons relate a cataclysim. One theory is that "the pillars of Hercules" Gibraltar was a solid mountain range that collapsed and allowed the atlantic to enter. Atlantis just happened to be in the way. As to exploring the stars, some people theorize that if an asteroid had not hit the earth the dinosaurs might be exploring the stars and we could all be little sloths instead of men today. Like the budists say "you can't step on the same piece of water twice". The stream keeps flowing. We can't prove or disprove it. The fantasy we have today becomes the reality of tomorrow. Before there was a pyramid or an empire state building someone had to think, "this could be"! The seed of these ideas were planted in all of us by the stories of the past. So what is your Ideal City? Is it long marble collonades like the maxfield parish paintings? Is it never ending towers like Star Wars? Draw your Atlantis, Plant your seed, and maybe some one in the future will say, "I got the idea from a picture I saw as a kid".