Jack sent me this last week. It's fascinating.
I wondered if the whole thing was a hoax, but apparently not. Snopes has no entry for it, and the Wikipaedia entry treats it as legitimate. So does the Smithsonian magazine. What a blow to the common anthropological explanations about human evolution! I realize this probably isn't new for many people, but it is really fun to think about.
The structures on this site were built about 12,000 years ago (10,000 BC) and perhaps intentionally buried with sand about 8,000 years ago. No one knows who these people were, what the massive buildings were for, or why they were buried. Just for reference, these structures were built during the last ice age and are more than 7,000 years older than any other structure we have yet discovered on our planet.