of sand into a protective shell around the twigs. These are the pseudopodia that are secreted by foraminifera. They're long, thin, tendril-like projections. What the foram does is it wakes up, sends out the pseudopods and then just grabs every particle in its environment and pulls them in toward its body. There's a certain pattern to the way that they sort the particles. They can select particular grains out of everything in the environment and just end up with them. They're beautiful masons. Could that be a very early appearance of intelligence? - I say it with great care. - Yeah, I have to say it with great care, too, because there are stories about how these particular organisms have fit into that debate. Turn of the last century, for example, there was a scientist, a British scientist named Heron-Allen who, apparently, during one of the debates in one of the British societies was pointing out the fact that every definition of intelligence that was being formulated could be fulfilled by these single-celled creatures. Borderline intelligence, yeah, at the single-celled level. I mean, it is a manifestation of the best of our abilities, really, the way that they build their shells. It's almost art. I noticed that the divers, in their routine, were not speaking at all. To me, they were like priests preparing for mass. Under the ice, the divers find themselves in a separate reality, where space and time acquire a strange new dimension. Those few who have