Of course it's real! Where else could the story come from? After all, every myth has its roots on the truth... یا something like that. Atlantis is probably just a great ancient civilization that was unfortunate enough to experience a natural disaster, therefore sinking deep into the ocean. Every great civilization always falls in some way... I don't think they're advanced, though. Like, high-tech stuff. I believe they're smart, so they built great architectures and discoverd many things, but not so smart that they had the technology that we have today, and more...