Wow. It hasn't really got much in the way of a throughline, it's mostly just nature footage strung together with some narration, but boy, it's some impressive random footage. If you have an HDTV, this is something you should be watching.
In fact, if you have an HDTV, it's something you should be renting on DVD and inviting me over to watch. For the twenty-foot manta rays, if nothing else.