I'm neutral regarding his theory of an ancient lost civilization. I've thought about this for years. I think there were many lost civilizations (for example, interesting megaliths near Japan). But, his documentary gave me an idea. Why not put together an interdisciplinary team of astronomers, geologists, archeologists, chemists, experts on human myths/legends, etc. to investigate unusual sites? They may come up with some fascinating theories (similar to some ways to Graham's).