A bio professor told me once that if the matter that makes up the tree outside the anatomy lab window were to be made transparent but leaving the tree parasites opaque, the tree would still be highly visible due to the population density of such organisms.
We scamper around the surface more or less unaware of what is right beneath our feet. Some geologists, roadside diner owners, and archaeologists scratch at the surface here and there, but for the most part we are as unaware of the half of our universe underneath us as we are unaware of the half of the universe above our heads.
We live on a thin plane, a two-dimensional section through the three-dimensional universe; and we live in the present moment as well, not seeing far into the past or the future. Generally-speaking, present company excepted. :)