In a way, cinema itself is the ultimate special effect: another world trapped onscreen for us to peer into. As the very first viewers of movies learned, shock and awe would always be a part of the experience. A massive revolution in digital technology has occurred within our lifetimes; Hollywood has reinvented itself, for good and ill, as a delivery device for fantasy and wonderment. So let's take a trip along the definitive moments—the instants when jaws hung open and we gasped at something that had never been seen. And if you've been knocked out by a title that didn't make our list, please let us know.