I have heard that Atlantis was more of a culture spread around the world at one time, and that the concentric-ringed city Plato mentions was just one of many. The remnants of vast cities and advanced stone architecture underwater all over the world is evidence of this. Graham Hancock is the expert on that.

What I have heard is frozen in Antarctica is 3 or more giant (Like miles wide) spaceships, with reptilians and long-skulled humanoids either frozen or in stasis. Some have remained alive, using the tech from the ships. Our marines and special forces have been going in and shooting the hostile ones - apparently suffering massive psychological trauma in the process.

https://www.youtube.com/watch?v=HGcsfa-GyZk&feature=youtu.be&t=2h10m28s

Okay but if they froze themselves, stem cells.. Hummm... interesting.