Documentary based on Eric von Daniken's famous book, which deals with ancient mysteries and specifically whether aliens visited Earth centuries ago. The gimmick in the book is to suggest outlandish theories but always to phrase them in the form of a question. This way von Daniken can always backpedal and say things like "I didn't say that the Bible has aliens in it. I just asked what if it does?" It's a clever huckster's trick but it served him well as he made a career writing books like this using the same technique.
I love the footage of the various locations and artifacts. That the footage has that vintage '70s look is an added bonus. It's talky and a little dry but still interesting and worth a look. As far as documentaries on ancient aliens or forgotten history goes, this is pretty good. For the absolute best in this type of material, you'd have to watch the Leonard Nimoy "In Search Of..." series.